Welcome to the website! You will find alot of good stuff here. Sounds like you have a great project.
If you want to get ahold of upholstrey kits you can get ahold of Kanter. I don't know if they have any orignial style interior kits but they have some really nice velour, tweed, and saddlecloth fabrics.
http://www.kanter.com/
For parts like power seat motors or door lock you can check out Fusick. They specialize in parts for big cars.
http://www.fusick.com/