I know that UIAppearance has been introduced in iOS 5, but is there any way of using the new protocol to reskin the MPMoviePlayerController, or do I still need to get my hands dirty using drawRect methods and the like?
Does anyone have any good examples of reskinned movie players for the iPad?
MPMoviePlayerController's user interface is entirely transparent for you as a developer. You can not change its appearance at all. You can only replace the UI by hiding the default interface and showing your own as explained in detail within the following SO answers:
To what extent can the iOS Movie Player be customized and styled?
Adding custom controls to a full screen movie
One additional note though: Even though this does enable you to create a customized movie player, Apple clearly recommends against doing that - and once again for good reason. The player, as is, does provide a well functioning, good looking and accustomed UI to the end user. Customizing the interface, in almost all attempts, will reduce the usability. Trust me, I have done it numerous times for various customers that insisted in having their branded player - yet I have never encountered a design that feels as good as the one Apple provides you with.