For the map, we would need to decide if it would be of just one world or of the whole universe. If we pick the latter, it would be a very long game. But hey, length is a good thing.
Jason, it would be good if you could formulate some rules, as you appear to be good at that sort of thing.
I was thinking for races:
Zerg:
Overlord and Keriggan. The Overlord maight have a few separate cerebrates (generals) controlling the army.
Terran:
Dominion, Earth whateveritwas, and maybe (if we decide to collaborate groups from different points in the story) the confederacy, Umoja, and Kel-Moria?
Protoss:
Conclave, Dark Tempar, Templar
Maybe some new fourth race?
Remember, Im not the mod, so you guys dont have to use everything I suggest. Im sure there are better ideas than mine out there.
Maybe we should nominate some people for mod and then set up a poll to vote for who we want? Of course, thats if anyone wants to mod. Its too bad I cant...