This is a small, naturally aspirated propane burner that I just finished. It runs like a top on 10 p.s.i., and can probably handle more. It combines features from a number of other designs. The best thing about it is that it requires no drilling or tapping at all. In fact it could be made entirely without power tools. Of course electricty makes things easier.
UPDATE: After observing the burner for a while and doing some additional reading, I think the propane jet should be much deeper into the tube, more like so: