Ditto on all the other suggestions... How about a strong roof support? A teardrop with a stable, strong, flat roof that you can stand on with your tripod for added height. Perhaps a rack that you can attach a couple ball mount clamps for either camera, lights, etc.. You didn't mention if your photography is only for outdoors, or will you do people portraits when you are not camping? The teardrop can be a portable studio with the right attachments. Maybe I am over thinking your request for solutions, but photography can also be broad topic.

Then again, you can always strap a small ladder on to the roof rack.
I took this photo while at the IRG 2012, standing on top of big rental truck. In retrospect, I wanted to be lower, but there was no ladder around in the woods. Quick bring that big truck over here! You can actually see the faces way in the back in the original resolution image file. Oh yes, I managed to get in this shot myself as well.
