I have a propane campfire I made out of a steel 15" wheel and some 1/2" pipe fittings. I got the idea from a place in West Valley that makes these, only slightly different. I drilled a hole in the side of the wheel, and built a "t" shape out of a cross, some nipples, a few caps, and a reducer where the propane connects. I think I spent $45 or so on all the fittings including the propane parts too (hose, regulator, valve, etc.).
As far as using it goes, it's fire. It's warm if you snuggle close, although it doesn't put off as much heat as a nice radiant wood fire. It doesn't have quite the same feel as a wood campfire either. But then again, you don't get the smoke stinking up everything, or getting in your eyes. You also have the benefit of shutting it right off when you are done. One significant advantage is that you can use it during most fire restrictions. I've got the backup e-mails from local FS/BLM agents to back up my case if need be. It's nice to have a fire when no one else does. It basically falls under a propane cooking device.
With the design I have, I can run it for probably 14 or so hours on a decent flame height when connected to a full 20# propane tank. I could turn the flame down and gain time, but most of the time I've realized I only camp 3 or so nights at a time, so figure 4.5 hours a night. Most of the time we only have a fire for 3 or so hours. I can adjust it to have about 18" tall flames if wanted though.
Having said that, it's another thing that adds weight to your load. I've seen plenty of other designs that are lighter, but when a nice breeze comes up all of a sudden, do you really want it that light, possibly tipping over and having set the forest aflame? I like this design because it's stable on any surface, plus with the burner being set inside the wheel, the wheel acts as a wind break.
