You might want to post this (or have it moved) to the new Long Distance forum where various Randonneurs and other long distance cyclists from around the world are discussing various long distance events including brevets, randonnees, and the 2007 PBP.
Also ....... Randonneuring is all about being self-supported ... being able to travel incredibly long distances and fend for yourself. Many, possibly most, of the participants in the PBP do the ride without SAG support of any kind. Really, SAG support isn't at all necessary because the ride is so well supported anyway. On the 2003 PBP, I carried everything I needed with me in a fairly small trunk bag ... the only thing I wished I had with me, but didn't was a very small, ultra-light sleeping bag ... and I'll be adding that to my bag in 2007.
However, if you're a member of RUSA, I believe you can make use of their SAG support.