Okay, here's some ideas I've come up with to adapt the adventures to Dark Sun. I think it actually fits pretty easily. Some of the changes seem like no brainers, like Rajaat/Kyuss and Dragotha/Dregoth, but if anyone has any other ideas I'd like to hear them.
So, Rajaat could easily replace Kyuss. Dragotha, becomes Dregoth, who's always been in search of increasing his powers. The harsh jungles to the south were Kyuss was imprisoned in a spire could become the Dead Lands.
The Free City? Tyr, obviously, there's even a gladiator adventure planned which'll fit perfectly. Diamond Lake could remain Diamond Lake only it's long since dried up and the mines are all at the bottom of the lake bed. Allustan becomes a preserver employed by Manzorian, an avangion also known as Oronis.
The city of Alhaster could become Celik, perhaps the patriarch of merchant house of Mareneth is a powerful defiler who has secretly been increasing Celik's strength and now styles himself the Prince of Celik? Or it could be Balic, and the Prince could be head of merchant house Wavir.
The Ebon Triad, instead of trying to merge Hextor, Vecna and Erythnul could have stolen obsidian orbs from Kalak, Boris and Kalid-Ma in an attempt to use the power within to revive Rajaat.
Finally, Lashonna. She is none other than Abalach-Re, revived somehow by Rajaat to be his pawn on Athas in his attempts to escape from the Black. In return for this unlife Rajaat gave her she must serve him, perhaps she's even controled by him. She could be somekind of vapiric sorcerer queen.
By the end of the adventure path the heroes will have befriended Oronis, allied with or defeated Dregoth, killed Abalach-Re a second time and prevented Rajaat from escaping the black, and finally come to power as the new rulers of the burgeoning city of Celik. (Or they could replace the merchant princes in Balic, giving Athas a second 'free city' to match Tyr.)
So, as you can tell I really want to run these adventures on Athas.