Of course you have to pick a car with a frame to begin with, but you knew that already...
Really though, there are a few frames that you can't use easily but with this hobby, just about anything is possible. I used an AMT frame from the phaeton or vicky, Kenny cut up a Lindberg frame and Jairus did it to a Revell frame. You have lots of possibilities so just ask about a particular kit before you buy it if you aren't sure.