For all you developers out there itching to get your hands dirty with TurnKey, this is for you! We have just released TKLPatch. It's objective is to provide a dead-simple way in which an existing appliance can be extended/tweaked.

Example tweaks include updating a configuration file, adding data files, adding a package, and even creating a brand new appliance leveraging a generic appliance such as Core, LAMP, Rails, etc.

Go grab the code, take a look at the documentation, and get hacking.
Let us know what you think, we love feedback.