It all depends how far along in development the RUU was, if most of the bugs have been ironed out it might be a month like you said, it could take longer, who knows?
all i know is now a working ICS base is in the hands of capable devs, so s**ts gonna go bananas soon enough, and any bugs in the current leak should be ironed out by them
NOKIA Lumia 920:Stock with all the AT&T crap removed
HTC Amaze: Stock ICS with all T-Mobile shenanigans removed
HTC Inspire: I forget :P
HTC Radar: HD2O Dynamics7 v1.21 Full Unlock with HSPL 2.05