That Cagalli is tempting... I've got an AU I'd like to swing, if I may. I play at savetheearth; characters have been reincarnated into new lives, and they regain their former selves' memories, possessions, and powers over the course of the game, at effectively whatever speed you like. We have an existing set of Gundam pilots; Banagher, Lockon (Neil), and Tieria, with a number of 00 pilots on reserve. I would personally enjoy seeing the Strike Rouge or the Akatsuki hovering over the skyline, joining the units already present. The pace might be a little bit faster than you're looking for, but it's definitely comm-based, and the AC's not bad - four threads with different characters in a month. You can still backtag stuff into oblivion, too. The game is plot-heavy, and you have the freedom to affect it about as much as you want, too; characters are welcome to start things and make changes, and the plot is moved along solely by character actions.

If this is something you're up for, I'm happy to answer questions; if not, that works, too. Regardless, happy hunting!