I built one out of a barrel, well actually two of them. The first one the barrel is standing up, it was an open top barrel so that became the bottom, I welded in a stove bottom in the ring bulge (it was a force fit). Then I cut a door in the center and fabbed up some hinges, made a collar for 6" stove pipe at the top. It worked quite well (only thing I would have done differently is I would put some sort of baffle in it) and the only reason I stopped using it is because I cut all my wood a minimum of 24" and they wouldn't quite fit. I didn't feel like cutting two different sizes so the second stove I went with the Volgazang barrel stove kit (the single one) I have always wanted to try one. I put the large bung down on mine and left it open, then I made a piece to cover it with four 1/2" holes in it but I can slide the whole thing out of the way. I tend to need a little more draft than the kit allows.
good luck
dave