Sounds like a great project Joe. I am on the left coast, so I probably can't be of much help. One suggestion though is to check with FEMA on trailors. I know they had alot of them left over from Katrina. Perhaps you could get some from them being a nonprofit!
Good Luck on the project. I hope you will consider ICF. Lot's of great ICF companies out there. See who is active in ICF in your area. ICFA can assist you, along with your local BIA groups. I am sure if you contact them they will be happy to direct you to Architects, Engineers, and other pertinent trades people.