Interesting that you should mention this. I have been looking at the same thing.
I have seen nice things produced in Google Sketchup. In playing with the free version, I found the interface a little difficult and ambiguous. I also found it hard to make things to exact scale. There is pay version of Sketchup, but I wasn’t going to front the cash for that because of what I saw in the free version. Sketchup also has the ability to add plug-in modules.
