John I've found the best source is the suppliers of the tools themselves. It might take some searching but generally they offer them as spares. The Torx + M-thread + head angle makes them a bit obscure for regular metric fastener suppliers even, but I can provide some seller links I've been happy with in that regard. I think a good strategy is when you buy an offshore tool, throw 5 screws on the order (which I am guilty of not doing).
Your original question - going to guess pretty slim pickkins in CowTown. But you never know. You might find a tool supplier like Skinner or DMH (Sowa distributer) but it will proably be a spare to a higher end tool (and more $$). Some of those are interchangeable, some are their own standards go figure.