Well... while this thread is a little wild for me, my upcoming campaign tentatively called "Forever" will stretch the d20 rules as far as they can go. It combines concepts from Quantum Leap, Sliders, and Exiles, wherein a group of characters are brought together from all over the multiverse to jump from world to world righting wrongs, and trying not to kill each other in the process. Any d20 game is available, as long as we have a book for it, and as long as I can adjust a few things to make them mesh. I'm even making new character booklets for my players that will integrate d20 material from D&D, d20 Modern, and Star Wars. (one sheet to rule them all...)
So far? Well, we've tentatively got a Jawa Jedi (LOL!), a WW II soldier (from V for Victory in Poly), a d20 modern paramedic, and a Hengyonki (sp?) from OA.
As tasks are completed, characters are able to be sent home after reality threads are repaired, or if they die... well... they're erased, and replaced with a new character brought in by the same player.
There's a few rough edges to smooth out (using hit points, where they get replenishment resources like ammo, and lowering the SW damage by one die), but I think it'll work out pretty well. If anyone cares, I might even do a Story Hour for it...
Thanks
Chris