This is a good question. There are many projects that offer different Android skins. It is not required to go through google to implement them. The 'skins' are basically just programs, like any app, but make the launcher UI look and act differently. In fact, many apps are available via the web and you don't have to go through the marketplace to install them! They feature a simple QR code that you can take a picture of on your phone for painless installation. You can also navigate to them using the phone's browser. So to answer your question: yes, someone could easily implement and distribute the customizations that I suggested without needing Google's approval to do so. Lastly, there's a rich scripting framework available as a project that lets you write scripts that interact with the SDK directly, so you can quickly create/test useful programs without publishing. Android is very open to customization, which is why many prefer it to other market alternatives.