It would be nice to do that, but if Apple has shown us anything, it's that you either play entirely by their rules, or you don't play at all. ANY attempt to circumvent this will just mean your app gets bounced, then you're fucked. Once you're in the game, you'll have customers who depend on that app being available on the iPad. You can't risk pissing Apple off, so these types of workarounds aren't going to work. Anything that just involves physical goods is fair game, but if you're offering anything that's accessible through the app, you're digging your own grave by messing around.