A well storage pressure tank may serve your purpose. There are reverse osmosis tanks that are designed to handle up to 100 psi (per Amazon item post) and ordinary well tanks with internal bladders that provide at least your specified 50 psi.
Bladder tanks will be larger than the water capacity, as half the volume contains a rubber bladder. Air pressure fills the bladder, pressurizing the water as the well pump fills the water volume portion. When the pump reaches cut-off pressure, the bladder is compressed and maintains that pressure as the water is drawn off.
Without a bladder tank, as your tank empties, the pressure would drop.
If you will be hand-pressurizing the tank, you are the cut-off switch and can adjust via air-pressure gauge on the air pump or fill nozzle of the bladder.
A quick search discovered bladder well storage tanks as small as 2 gallon, 4 gallon, and 14 gallon which makes it more likely one will find a 10 gallon capacity.