I have a windows box, a mac, and an old, old, old laptop with linux on it. I may be getting a surplus sun box as well. Not sure if I'll have the time, but it would be pretty neat to run a game using all 4.
You might want to exclude the Windows box from the game, due to the battle replay incompatibility bug. If the Windows box hosts, all players except that box see incompatible replays. If another box hosts, the Windows box will see incompatible replays.