If you want a finished updated look, the example vantexan gave looks great to me. Cabela's sells or did sell a tent along the same idea. Hooked up to a truck with a camper shell. Of course there is nothing wrong with the homemade look. Gage has a very nice example and the canvas would give you that dated look as well. Really look good with a 40's design and 40's ride to pull it with. Although, I do not think canvas would be my choice, especially for summer camping. Remember the canvas scout tents when I was a lad. Getting harder to breath just thinking about it. But then again, you are not going to be spending a great deal of time in it.
Saw a guy on TV who made a "dressing room" using an opaque shower curtain. He curved a rod in a semicircle and just hung the curtain around it. Looked better than what I make it sound.
Show us a pic(s) of what you come up with. It is great to see other ideas.
One of the things that appeals to me about this HOBBY.
Cheers,
Eagle