Homes for Our Troops (Hfotusa.org) raises money to build a new home or adapt an existing home for handicapped accessibility. The finished home is then given to a disabled veteran. All services and materials are donated.
Wounded Warrior is another good one.
Homes for our troops built my cousins home. What a great organization! He is a triple amputation vet. The home they built him is amazing. Thank you for mentioning them Kate!