I've, uh, been thinking of kingship in Mesopotamia and how the theory of divinely inspired kingship in selfsame is said to have been current since around 3000 B.C. or so, which period is shading off to Near Eastern proto-history, so it would then seem almost sui generis as well. There are some scholars who claim that the institution of kingship is a relatively late political development and that Sumer was previously organized along the lines of 'primitive' city states, but opposing parties claim that there's really no evidence for that, textually or otherwise.
I've read parts of S.N. Kramer's translation of "Enmerkar and the Lord of Aratta," one of two strange and complicated myths (the other one being "Enki and Nihursag" which I think is about the creation of an idyllic paradise situated in the island of Dalmun by the god Enki) that deal with how the Sumerians imagined their origins, harking back to a sort of golden age. The first myth alludes to very remote times when people paid homage in one language to Enlil (literally, "Lord Air" and one of the three principal gods of the Sumerian pantheon; An or Anu, the sky god, used to be considered the sovereign deity and the highest power in the Mesopotamian universe, but at some unknown date the theologians of Nippur supplanted him with Enlil, who then became the 'force of heaven,' 'the king of kings' who chose the rulers of Summer and Akkad and 'put on their heads the holy crown' XO) until rivalries between the gods and their worshippers led to a confusion of tongues, a theme which we know recurs in the Tower of Babel.
Anyhow, these stories seem more like routine doctrinal statements of racial affiliation rather than a coherent discussion of prehistory, or what the Sumerians might have thought of as their prehistory. Sumerian literature doesn't offer any close parallel to the Biblical story of the Lost Paradise, though the legend of Adapa does come close to a Mesopotamian account of the Fall of Man (Briefly, Adapa is a 'model of men' created by Enki to serve him. However, Adapa offends the god Anu when he curses the wings of the South Wind -- in the form of a big demon bird -- after the boat he was riding on capsized in the sea. Anu summons Adapa to his palace to be punished. Enki tells Adapa to clad himself in mourning and show signs of grief at having angered the gods. In this way, Anu's heart will soften and he will forgive Adapa. But, Enki continues, Adapa must never accept any food or drink offered by the god, the 'bread of death' and the 'water of death,' because he will then forfeit his life. In the end, Anu does forgive Adapa and offers him, instead, the 'bread of life' and the 'water of life.' But Adapa, following Enki's advice to the letter, refuses the gifts that would have made him immortal. Whereupon Anu dismisses him: Take him away and return him to earth. < -- Now, the interesting thing about this story is that you end up wondering whether Enki's proverbial wisdom failed him -- he is worshipped for his unrivalled intelligence among the gods; there's this long surrealist poem showing him putting the world into order, attributing 'the Destinies' and creating mankind -- or whether he deliberately lied to Adapa. But the result was that Adapa lost his right to immortality. He lost it through blind obedience as Adam lost it through blind disobedience. In both cases, man had condemned himself to death).
Okay, right. The thing is, however, that the parallel to the Bible goes no farther than this. The Sumerians didn't have the same passion for genealogy like, say, the Hebrews who created an entire unbroken ancestral line going straight back to Adam. Sumerian gods had created mankind for a specific purpose: to serve them. They had fixed the details of this service, they had exalted the 'divine ordinances.' Humanity, however, was always being led astray, so they needed kings appointed by the gods to enforce the divine law. So, almost immediately after the creation of mankind, 'the exalted tiara and the throne of kingship' (as described in "Altrahis," if I remember correctly, must check) were lowered from heaven and from then on a succession of kings led the destinies of Summer and Akkad on behalf of the gods (specifically, Enlil).
There's an extant Sumerian king list -- giving the names of kings from the beginnings of monarchy up until about 2000 B.C. or so -- compiled from different documents by Sumerologist Th. Jacobsen in the 1930's. The kings themselves are listed according to dynasty (Though not in the sense one usually understands it; a dynasty seems to be just a particular unbroken succession of kings instead of an actual royal family. Once the kingship is passed on -- or, more precisely, lowered from heaven to another place or person because of a king's infraction(s) against the gods -- a new 'dynasty' starts). Most of them seem to stand at an epic incredible scale in relation to the rest of humanity. These mythical (well, half-mythical, because scholars say some of them might have existed historically -- check out the Enmerkar and Lugalbanda epic cycles) figures rule on the average for several thousands of years, granted (an uncertain if theoretical) immortality and superhuman abilities by the gods for their obedience to the divine orders and for their service towards both heaven and their own subjects.
This line seems to have been interrupted by a cataclysmic 'Flood' -- also mentioned in the King List -- when the gods presumably did get pissed off and decided to do away with the world as such so they could start from scratch. There are very interesting theories about the Flood -- did it really happen, was *this* Flood eventually interpolated into the Biblical text in the form of Noah etc, or is it merely a subtle didactic Sumerian gloss on the perils of overpopulation, and so on -- but what I'd like to point to in particular is a retroactive reference to Gilgamesh. Enki warns Ut-napishtim, son of the king of Shruppak (or is it Eridu), about the gods' intention to destory the world through a deluge and tells him that he must build an ark for himself and his family if he wants to be saved. Ut-napishtim does so. The Flood then begins; the gods regret their decision almost immediately, but there is nothing they can do. After seven days, the rains stop, the waters start to recede, and they discover that a few human beings -- Ut-napishtim and his family -- have survived. Enlil is initially furious but Enki pleads his cause with his usual eloquence, and Enlil finally agrees to grant Ut-napishtim immortality, the true eternal life of the gods that is independent of their good will towards a certain individual. Gilgamesh -- in the epic cycle "Gilgamesh" -- searches for Ut-napishtim, thinking that he might tell him how he too can acquire immortality. Gilgamesh does find Ut-napishtim but fails in his quest for eternal life and his epic ends with Ut-napishtim's own words: "Do we build houses forever? Does the river forever raise up and bring on floods? The dragonfly leaves its shell, that its face might but glance at the face of the sun . . . The resting and the dead, how alike they are." So, there seems to be this implicit break with the nature -- not the concept -- of kingship ca. before the Flood, the age of the superhuman kings, though it must be inevitable because the Flood overtly marks the replacement of one human race with another. Cool kings -- getting more and more historical by the minute -- continued to get in on though, but their race for teh Meikun vibe had begun to assume fabulistic dimensions, more the stuff of self-contained moral lessons rather than prologues to fantastic pseudo-Fortean chronicles. However, the almost obsession with immortality, how to live forever in whatever form, remained a stable thematic. There's the Etana legend, dated after the Flood, a story about a king called Etana who wanted to ascend to heaven to get the 'plant of birth' because he desperately wanted a child to call his own. The end of the tale is unclear because of lacunae in the tablets in question, but Etana did get his son and managed to live a respectable 1000+ years as well.