Earlier quoted context omitted.
I actually would've thought the MS Windows Phone App Store would be even more fertile ground. Not sure how stringent their policies are, but a quick Google search only turned up a rejected Twitter content scraping app which was rejected. Not to mention if anybody needs more apps, its the Windows Phone App store.
The WP store is a little more relaxed than the iOS app store - but - it still doesn't have any way to sideload any apps, which means it's still up to Microsoft, a single central entity, to decide what apps you can install on your device. The same is true for any Metro apps.
At the very least, WP is different from iOS in that their SDK is provided for free (using the express edition of Visual Studio).