They do sell the device that turns on the Vac from the air flow of the sander triggering it instead of the usual electric circuit on electric powered sanders.
May as well ask here, are there any advantages in using an air powered sander compared to the electric motor driven one? I speculate that they could be cheaper to make, lighter, less prone to wear out.... Anybody here use one?
Read up on the air powers pneumatic sanders, apparently they are extremely effective; no swirl, long service life, easy to repair, low vibration. Only drawback is the need for a compressor, might be worth looking into...