If you have the money it probably would be better to make a big rigid air tank in a backpack and regulate the air output. That'd get you more pressure more easily with more common parts.
I will try this, but it seems large and clumsy. For now, I will work on this idea and see if I can make the bladder by using tubing. Perhaps if someone bought tubing in bulk, we could all buy a foot or so for a price (the same way PETG is sold).