These might also be worth doing.
We have the "Mote in God's Eye" Universe (Niven/Pournelle). Empire of Man, the Outie Rebels, Sauron Supermen, and the Moties. You could do some very interesting population effects for motie planets
Saurons have very slow growth but incredible ability, etceteras...
And there is another favorite of mine, the Merchanter/Alliance/Earth Company wars of CJ Cherryh. "Cyteen" trilogy, "Downbelow Station", and a host of other stories/books. Might make for interesting mod ideas....
Someone tell me when to stop thinking of this stuff