sure. there are a few places that sell plans and parts. and books on how to setup and run your cart too. bens carts is one. http://benscarts.com/
he sells plans and parts kits. and most things you would be for your cart. plus he has good service and fair prices. i.e. most people charge up to 80 for a dog sled, a prep area to build and set dogs for customers, I have seen these for around 20 dollars at times.
p.s. I do not work for bens carts or get anything for my opinions.