The standard Apple TV remote only has the navigation buttons, a play/pause button, and a menu button. However, in the Settings menu, you can train a standard Apple TV to respond to another remote. When you do this, it also supports some extra discrete buttons:
Skip back (10 sec)
Skip ahead (30 sec)
I can’t get Media Player to respond to these buttons from my 3rd-party remote (the one that came with my DVR, although others seem to be having the same problem with Harmony remotes: http://forum.firecore.com/topic/5684 ). However, they do function perfectly in the standard Apple TV apps (iTunes, Netflix, etc).
I know these buttons are not on the standard silver Apple TV remote, but since the stock Apple TV software does support them, I hope you can support them in Media Player too.
PS. I’m sure the developers know about these extra buttons, but for anyone else who’s curious, here are some more resources on setting them up: