[PvK]

I think it's quite possible to do that in Proportions, especially to have some empires who have developed colonies for a long time, with others who haven't. The main reason is that colony development and research take a lot longer time to develop to excessively high levels, while ship and construction are still relatively quick, though capped by maintenance costs (though, it could be interesting to have one of your older empires have a large stockpile of mothballed ships, if a human were going to play them).

A big research advantage could lead to some balance issues, I suppose, depending on what the older races researched, and whether they were going to be a player race or an AI race. However, since in Proportions the tech tree is steeped AND it isn't possbile to multiply your research rate they way the default set allows, the head start races will only get so far ahead, unless you set research cost to Low or do a ten-homeworld start. I think I'd recommend single-planet start with high tech cost - this should naturally keep anyone from getting really high tech stuff even after a long time head start.

Another concept is to have one or a few empires that have fairly large widespead colonies, but who aren't in a good position to defend them all.

Anyway, it sounds like it could be a really interesting scenario, and I'd hope it would work well. The more human players, the better, though, as always.

PvK