Okay, I checked out all of the shops here that you cite as teaching in BP/W, shoops that you cite as examples of PADI shops unwilling to do this. Most of them are PADI shops!
Now, Most of them are also GUE shops, and that includes EE (Extreme Exposure), one of the shops I was thinking of myself. For those who don't know, EE is the home of GUE; its owner is also the owner of GUE and Halcyon. EE, of course, focuses on GUE instruction, but it also offers PADI instruction. Its owner does not teach any more to my knowledge, but he is a PADI instructor (as well as other agencies). Until a couple of years ago, almost all of its OW instruction was done through PADI.
I never said they were not PADI Shops. These are the shops that teach mostly in BP/W. However, the shops I have dealt with or worked for in the past discouraged this method of teaching—and is one of the reasons I left. IMHO, it is better to teach in a configuration (BP/W Long hose) that is just as good for recreational as it is for technical. Why buy two sets of gear if you decide to move to more advanced diving?