Have you reached out to Bill at WTB Woodworking? I think he might have a CNC big enough - or he will know who you should call. Great guy and a great shop!
EDIT: Actually, just noticed on the website, they have a 5' x 13'6" CNC.
WTB Woodworking is a retailer of woodworking equipment, supplies, Lumber and Slabs for the home hobbyist to the professional.
www.wtbwoodworking.com