Bill writes:
small torque sensors that can be clamped to a rotating shaft that
transmit their data wirelessly

Yes, for torsion the classic setup is a wheatstone bridge strain
guage array feeding a telemetry transmitter. I shopped new digital
transmitters a few years ago but didn't buy, hoping for better prices
and bandwidth later. We'll see. In 99/early 2000 we used a wheatstone
bridge and a borrowed analog transmitter from Wireless Data. The
bridge was still on the propshaft at S&F that year. I was there all
week and nobody ever asked why the propshaft was wrapped in strapping
tape g.

Dan