The best you can get in this respect probably is a humble bundle package (DRM free, crossplatform and keys for various platforms). But even they don't offer a free version on the iTunes Store or the AppStore if you've bought a game elsewhere as it's not part of Apple's business strategy, at least yet. I doubt this will change in the near future. Actually you can't even delete Lite versions in the App Store, oh well.
Last edited by taumel; 06/12/2011 at 10:13 pm.