Ok, I took some time for thinking of an interface that most applications could use (specially those who think sendmessages is too complex).. Ended up with a very basic "keyboard" interface.
Basically you can type any known skin command (i.e. "up" or "down") to control Road Runner -- Don't worry I'll still make a regular keyboard interface (arrow keys etc).
The idea here is to make it easy for Girder and other applications that can simulate keypress to control Road Runner with simple configuration. In girder for example you can simply say simulate keyboard and enter "audio" to make the software go into the audio player using the remote control device attached to girder (so no complex sendmessages). The SDK with sendmessages is still valid, but this opens a window for easier interfacing.
I'll try to make a girder config file for the Girder fans out there.. just want to know if there's anything someone would like to add or change in this interface, before next release which should include at least some ID3 support already.
Let me know your thoughts, the above is already implemented (just not on site yet).