A while back I lost the head from my el cheapo tripod. I couldn't find a convenient replacement head, so I carved one out from a piece of wood. A counter-sunk stainless steel bolt attaches it to the camera. I cut an angled edge on the front, and gouged out a little spot in the back for attaching it to the tripod.
I thought it would be a stopgap measure while I found a real replacement head, but it turned out to work so well I just kept using it.