The one thing all the *cough* possibly biased (and always pestered) modders didn't bring up is that creating a "just for fun" competitive mod would be possible.
Rather than add all the stars, planets, orbitals, ships particles, textures and abilities from everything--just having the primary ships (and possibly special orbital structures) available in the game.
You could even skip the research trees and the like and make everything instantly available. You could make it even more manageable by making it require map templates to use the various ships--so anyone could play any ships they wanted and no production and research muss and fuss required.
Once you decided on which things you wanted in, you could balance them against each other in the way you felt was most fair.
I'd look at it as a cross-mod demonstrator and I bet it would be fun.
I wouldn't expect the modder's from other mods to do it for you though. It is a lot of work doing all the things that go in a mod--very few of us are good at all of them or even know how to do them--and most of us have day jobs too.
Learn yourself and it will be a snap (be sure to get permissions before you "borrow" anything though).