Now this is Just me....But I have never been to concerened about titling or registering my Builds when I buy a Donor vehicle, to clarify, Thats the last thing I do, Or attempt to do, there are several ways around this in any state, you just have to be resourceful. My focus is on getting a Good Donor vehicle to do a Resto on....It might take me from 6mos to a year to do and in that time I work on getting it titled....just depends. In your case...get your Parts, Body, Frame...Gitter built...gonna take some time anyway...And work on the Last hard part, Getting it titled...Now, if you cant, you can always sell your build...just do Nice clean Non hack job work and you can get top dollar for her. while there may be alot of HMMWV's out there "Relative speaking" ....most are dirty, grimy, leaky rigs that Need some TLC....
IMHO I doubt you will find a titled Body...but not impossible, I wouldnt worry about the frame, they have no ID of any sort that is used in the Titling of the truck..that is I guess unless a past party had it done to satisfy his or her titling requirement....