Are you looking for something that self inflates like the life jacket does?
For DIY stuff, check out http://www.genuineinnovations.com/. They make many bicycle related CO2 inflation systems. I’m sure if you experimented with the volume of your product vs. size of cartridge you might be able to use a system like that.
In terms of inflatables, there is a company in Nebraska (Omaha, or Lincoln) that makes those giant inflatable “costumes” that you can wear. I think those are inflated by fans though. You might be able to pick their brains about inflatables.