I really liked my sandfox 4 seater. I thought it was the perfect frame. A 4 seater that was not too long and I also liked the higher side bars. Here is a link to pics of my build.
http://hoffmangallery.com/gallery15/DuneBuggy-BuildI am 5 10 and I had the front seats pushed as far forward as I could. Notice the steering wheel is almost touching the windshield. Then I put the rear seats all the way back to the torsion housing and tilted all the seats about 15 degrees.
When I was all done, adults could ride in the back. It was not that bad but a little tight. However, you can only use fiberglass seats. You will not be able to fit suspension seats.
Another great sandfox build in Aboone's silver buggy. You can search the forum.