I had an idea on this... What if you made a .ppf of a mod, and applied it to another one? If I understand them right, it only changes the things that are different. In other words...
Example:
Original Map: 00000000
Original Mod: 10000000
New Mod: 00000011
So if it takes what different between the original map and original mod, you get (1)00000000. but put that onto the new mod, and since only the first part is different, thats all thats changed, so you come out with 10000011, the two spliced mods. (obviously it would paste over existing mods, like say, warthog over warthog, so the original mod's warthog is gone. But if the only pistol is modded in one, and only the sniper in the other, you now have both pistol and sniper

.)
This would be an awesome way for teams to get the mod around. Just work on your specific weapon, ppf it, send it to the team while they send you their weapon, patch it, and play! Quick, easy, and efficient.