i made my own out of flat bar from home despot. it is very simple. i wanted to post a pic, but i don't know how to. anyway, the 20" tube on etsy is beautiful. if i had it to do over again, i'd probably buy it. i like the hinge. very clean looking.
upon closer scrutiny, i noticed that the aluminum tubes do not nest inside the other. they close up parallel to each other. if you look at the attorney's bag in the OP's thread, the top bars are nested. i'm not sure this would work out (or how it would look) on a doctor's bag.