I had a Peak Scientific compressor - around 25l, dentist job, silent as anything, and pretty useless for mist-cooling. With a low CFM and a small tank, it exhausted quickly, even just with a hand-help airgun where I could regulate things myself. The main problem was the low duty-cycle for the motor - after an hour cutting, and cooling, the compressor would overheat and cut-off until it cooled... that's when the WD40 would come out and smoke-out the shed.

Here's a hint: Unfortunate, but true, there's an awful lot of pubs going to the wall. I recently found a 50l (not much bigger), but similarly silent and 100% duty cycle compressor from a clearance of a brewery that had gone down the swanny. I'm not proud of taking advantage, but 40 quid later and I'm giving the old compressor away. Keep an eye on the auctions.