d20 ÆON + d20 Lone Wolf
The Aon Project is a fan club of Joe Dever's Magnamund, and the name got me thinking that Lone Wolf is the closest thing to an ÆON-style fantasy setting.
I'd like to play in an eternal-champion-style campaign using the three eras of ÆON and the d20 Lone Wolf RPG; each player would have a version of their character appropriate to each era, with the action shifting between eras mid-game, Cloud Atlas style.
Obviously, this would be a game for folks who enjoy building characters.