You could look into hoppin hydros for some parts. Do a search on e-bay and you will find a bunch of stuff. Wheels, tires, and chassis kits. There is even an e-bay online store for these items. They also have LED strips for underlighting a car.
As for rc cars, Revell used to make their RPMZ which was a 1/24 th scale model rc car. I found some at a clearance store for $20. In the revell catalog, they have pre painted bodies in a Mustang, Challenger, and 2 Nascars.
Kyosho made the Mini Z, and was sold at Radio Shacks for some time. These cars had alot of hop ups for them. Videos of these can be seen on youtube.