Today, I actually tried something out. My brother was at work and has been putting up a couple aquariums (including a huge 6' wide one), and that left a lot of excess tubing lying around, so I started thinking.
It may not be much to the inflation suit makers, but its a simple thing to do. I got a bit of the tubing, a heavy duty garbage, and some of the tubing. I detached the shower head in my shower (mine was simple, I just unscrewed it), and attached the hose to it. Then tucked the garbage bag down my shirt and underwear, and secured the hose in the bag.