well, some tips-

DON'T USE BATTLEFLEET GOTHIC!!!! Not because the devs for BFG will not let you (they would if they could I'm sure), but because Games Workshop (GW), the makers of Warhammer 40000, (and by extension, Battlefleet Gothic), have restrictive rules for their IP. So, only TC mods of GW's IP are allowed.

Why'd I say the above? Don't want a mod like this to get shut down.

Anyways, I'd suggest the following- Star Wars Requiem, Babylon 5, Dynamic Battle System, Homeworld Mod, SG Races/Galaxy, and possibly the Mad Scientist, Distant Stars, and Celestial Bodies mods.

7DS is copyrighted by DANMAN Games; also it's too big to merge w/ anything else.

You know, 7ds is coming to Entrenchment. Slowly, but it is coming.

Also, in regards to the OP, whatever mods you eventually decide to merge, make sure you have permission from the mod creators to do so.

ResidentCody, there's just one problem: LAST STAND HASN'T BEEN RELEASED YET!! However, a future version if this mod could include the Xin.