I've been having fun using Google's Sketchup this year. I'm not experienced with 3D modeling, but this app makes it simple. Mac and PC versions!
I've modified a Tatra 815 8X8 I found when searching the 3D Warehouse. I tinkered around with the idea of two roof-top tents to increase living space.
It's a really cool tool for wrapping your head around what a finished project could look like.
Tatra 815 8x8 C&C
Tatra 815 8x8 Expo