I've heard urban legends of folks who had fabbed such tang-bending fixtures but have never seen any of them or talked to anyone who claimed to own, have used or have ever even seen such an animal. Over the years I've bent several, as well as re-bending some of Bubba's efforts, and always found that 'tailing' it while using a hand-held template like Steve's was the best approach, at least for me it has been. The open access to both the top and bottom of the tang allows localized heating by the OA torch without the aggravation of having the clamping fixture suck the heat away from the area to be bent.
I did, however, fab a useful little wall lever-bending jig, allowing easy removal of most of the over-center lost motion in the wall's linkage design. Frank de Haas details making & using this fixture in several of his single shot articles.
Regards, Joe