Shoe update
I haven't managed to persuade myself to go to the airport without shoes yet (actually, I'm afraid of smacking my feet into something, or letting them fall off the footplate - shoes are good for something even if you don't walk), but I figured I'd report on the last 4 DEN-ABQ trips.
The first time I was told I had to take my shoes off, period. I asked if they could be swabbed - no. I pointed out TSA policy on PWDs, and was told that was only if the shoes had orthotics (!). Finally, I took off my shoes.
The next trip I hit on what is so far the magic phrase. When I am either told that I must take my shoes off or asked if I can take my shoes off, I say, "You can take them off or you can swab them." Note that I am not saying that I am incapable of taking my shoes off, because that would be lying.
So far (3 times), the screener has considered my statement and decided to swab.