I liked the blog post about Combining 2-D and 3-D techniques very much, but the others are interesting as well for game makers:
http://blog.rough-sea.com/

That's exactly the technique I've been using. I build a simple version in WED and paint over it. You don't have to worry about perspective issues this way.

I also used this method a while ago on some 2D pictures
of structures.
(FULL, Destroyed, Buildup)



First making 3D Models, render them in a fixed lighning and
angle, then repaining details on them.
Its the best method to create nice and coherent 2D Art
without having to be a great 2D artist.