I crewed this year for RAAM and I would suggest you get in touch with other 8-person teams. I crewed for a four-person team and I think it would be different with that many racers. There are pros and cons to RVs. Some teams don't use them and they are a huge expense and could be something that could be done without.
You may try medical centers and medical device companies for sponsors if there are any that may be used post head trauma.
Sleep deprivation was a big issue for me. Some of my crew did not pull their weight and some of us had to step in and it was rough. You really have to be able to work on very little sleep. Even when I got an hour or so I felt a lot better.
Your crew chief needs to be someone really well organized and not afraid to make tough decisions.
It is seriously a huge undertaking, but that being said, my team, Team4hivhope, which is made up of HIV+ racers, is already planning next year.