Creating new car models for Codemasters games in the last years has been pretty unheard of, if not extinct. I really don't think that will happen again. Rockstar Games tried to prevent modders to create real car models for GTA 5, modders eventually cracked it but it took a good while. Shows that game developers probably don't want models in their games that are not licensed for it.

But for car liveries and skins, Codemasters even encourage the players to make. Should take a very short while until the first new liveries pops up.