Hey now! We don't need to go cuttin' up any Valiants! :D
You can buy pretty much everything you need new, it just comes in sections and what you can't buy is pretty flat and easy to make.
The panels to replace both rear wheel openings and behind the back wheels will set you back about $800 IIRC, if you need all 4. About $200 each, I need a 4 and then some myself.