m8 u wil have to bit more specific. there are modded lobbies i believe running again for mw2. xpg also has a mw2 saveset for campaign. but i am not sure what you mean by multiplayer save?
If you are on about the MP-data file then all you have to do is load up splitscreen and start a game then give the file to me and i'll unlock everything apart from the spinning 10th