I have a 94 pace 34ft and have decided to do it myself, I found this http://www.outerland.com/RV/
DIY project on another forum and checked with a construction contract friend of mine and he has a bunch of leftover EPDM that will fit my rig so I buy the glue, some sealant, tape and a few new covers. Looks like it may turn out to be about $450.00 tops.
If you know any contractors or see any businesses getting their roofs done it would be worth stopping and asking if they have scrap. My piece was 15ft x 42ft. Cost me a case of beer.