I think most people graft in a front clip only. And I'm not sure it turns out to be any cheaper than an aftermarket front suspension. Its certainly not as rigid as aftermarket clips.

Remember that a car body supports the frame its built on and the truck cab and bed won't. It could fold up in the middle. A truck frame supports itself using no support points from the cab and bed. That's why you can't simply saw off a car roof and make it a convertible. The roof supports most of the middle of the frame.