Some are using the Volvo pump from the diesel series. I don't know how quiet it is.
My Compcams pump is noisy but installed in the engine compartment behind the a/c compressor so it's noise gets lost a good extent by the noise of the engine.
It isn't on all of the time. It cycles and if you use it with a vacuum storage can it won't run as much.
Where to put it is as much of an issue as the noise. Possibly more?