I have recently had the chance to participate in one of Daniel K's class, he is one of our awesome teacher of the 1st Semester in our AEC Concept Art Diploma at Syn Studio. He and his colleagues from Warner Bros. have put in place a very efficient 2D/3D concept pipeline using SketchUp and Luxrender.
For now we are just messing around with some basic textures and blocks but it's already very interesting, the renderer is not the most stable however it gives great results rapidly.
Here are some of the latest experiments, I'm counting of learning SU more and see how far I can push this cool technique for my Carambole project.
The whole idea is to prepare your texture first and then push/pull from there, then adjust the position of the texture according to your modelling, super fast and fun. Of course at some point it crashed and some elements in my scene got lost, make sure to save all the time! I ended up with this grainy version, it gives a good idea of what can be done though. Below are some other rendering tests...