I think the OP is on the right track. Put the accelerometer on the seat. Measure data from a few hundred miles. Stick the same instrumented seat on a different frame, but same wheels, tires, pressure. Ride a few hundred miles on that one.

Tranform the data into the frequency domain, and look at the magnitudes and frequencies where most of the vibration is happening. It would be interesting.

I don't think it would sway the true believers. They can't be swayed. How many golden-ear audiophile subjectivists have been swayed by science?