The Dsitz is the original alpine rappeling technique and was the only technique taught when I began climbing. As the video shows, you need only the rope (and a secure anchor) to use it. Back when it was in vogue, climbers regularly sewed leather patches on their pants and parkas to reduce the inevitable rope burns. There is a great classic photo from the 1950's showing a dsitz rappeler in mid rappel from The Maiden, a rock formation near Boulder which features a 120', overhanging free rappel. It works just fine if you are well padded.

Even today, the Dsitz is occasionally useful, especially when time is short and you don't want to bother with putting on a harness, etc. In my opinion, you are not well trained if you are not capable of using the dulfersitz.

A technique similar to the Dsitz is the French arm wrap rappel - stand with your back to the rope, twist the rope around both arms, and go. This is useful on fairly low angle slabs. The leg wrap technique comes from arborists and tree climbers, I believe. I don't think it would be very useful on rock - you want to have your legs free and mobile.