Thats what 7 deadly sins is. DANMAN just takes the factions out of each mod released (that grant him permission of course) and then combines them all together.

Yeah.  So far the Star Wars mod is in, plus two races from Star Control 2, the Ur-Quan Kohr-Ah and the Ariloulaleelay.  And there are playable pirates in the form of the Rogue race plus semi-clones of the original 3 races with new techs and features.  Consider them similar to the Generals in Zero Hour, or the sub-factions in Kane's Wrath.

And the most OP faction ever, the Atlantians (no, not the Stargate ones, sorry).  These ones are even more freaking powerful, and over three times as arrogant (well in the backstory they are, too bad Sins can't do machinima or everyone would be lol'ing in their pants with this mod in action).  But they are the ultimate techers, completely unstoppable later game, provided the player isn't a complete moron.

I missing anything else CanadaMan?  I know DANMAN merged Bailknight's, Lost_WLD's, and Solar Flair all together as well, plus SINSounds for enhanced sound effects, and Sins Plus and Solar Sins.

Well, so far its really just DANMAN and his army of playtesters adjusting for balance issues.  Nothing that hard to be balanced has been modded in yet, just the Empire has been added in, and the Kohr-Ah, Arilou, and Atlantians have been built from scratch so balancing them is easy.  The semi-clones are pretty similar to their bases, so balance there isn't too hard.

Once more things start getting added in, like the Star Trek mod and the Halo mod, then things will become hard.  Especially if the BSG mod gets added, and we have to find a way to have three shieldless races not be useless, and also be different from each other.  Balancing armor/HP/SP/damage values isn't too hard, as we are using vanilla Sins as a base, and checking our units against the vanilla ones in terms of power.  So things won't be that hard to balance out. 

Hard part is making sure the races don't just look different, they play different as well, so a Klingon attack will not be responded to the exact same way as an attack from the Empire.