I got a sears ?5gal one years ago, and picked up the regulator separately. I charge it when needed, and can silently use in when family members are asleep. Can get 3-4 moderate sessions out of one pump run, using a separate electric air pump to get the tank pressure up to >50 PSI. My pump is almsot intolerably noisy, though -- would have done that differently. I use a Badger single action for large areas, and an Aztek double action that I honestly regret getting. Their nozzle system is a pain, and the brush is ahrd to clean.
Paul Boyer at FSM is an advocate of getting standard compressed CO2 cannisters charged at an industrial supplier. Says he can get weeks worth of silent use out of one charge, and the cost is negligible once you've got the cannister. Never looked into that, though.
Truthfully, AH has pulled me away from modelling for a good while -- you're getting the guilt meter rising, all those boxes in the closet....