> GPL backers like the FSF are who enforce GPL'd software not being in the App Store. They feel that the GPL is incompatible with Apple's distribution mechanisms, since it's impossible to "distribute" a modified version of the app to iOS devices without going through the App Store. But if a group decided to upload their GPL app, Apple isn't going to check, and won't kick the app out of the store on GPL grounds.
What if someone sold an iOS app that could be downloaded from the iTunes App Store that "contained" the source code? (Actually, it would detect whichever app started it and would download the source on demand.) Combine this with a free app and service that lets people use on-air provisioning to get modified versions of apps?
You don't need to include the source code to be in compliance with the GPL. You can easily have it downloadable from your website. You only need to provide it for about 3 years (IIRC). You can just have a note in your 'About' screen: "This is GPL software, go to http://www.example.com to get the source". That should suffice.