I have been thinking of creating a Beer Engine. As an original is a bit hard to get a hold of I was thinking of adapting a manual Caravan plunger pump. They are not much different than a bike pump but food grade and better valved.
They pull water from below floor level to the sink once primed. I know the cask would have to vent but maybe it could be purged to slow down oxidation.
Any thoughts on the subject welcomed. In my case I would be considering using my 6 litre Tad Bottles sitting in a esky of ice. I could dicky the pump to operate by a ornate handle as I could mount the pump horizontaly under a bench.