I happened to download and install driver version 280 last night (64-bit Win 7, international driver) - it certainly does have an nvmm.inf file.I'm not sure if this is a red herring or not. But on my 64bit drivers there is no nvmm.inf BUT another file named nvpg.inf appears to contain similar information. When I get my cinema set up again (just moved house) I will check it out and report back...
Otherwise those with 64bit Win7 might care to check themselves.
Edit: it might have been 280.19 that I installed - will check tonight. I see 280.26 was just released.