Here's some info on the interrim up armoring
http://www.defenselink.mil/transformation/articles/2004-12/ta120204c.html
I had the pleasure of sitting with Major Rodgers on a recent flight, and he assured me he and his team had been working very hard and that a substantial number of Marine HMMWVs in Iraq had been upgraded, if not most.
I certainly hope we get something like the RG-31 soon.