Although there's nothing currently on the developer site which explains explicitly how to do this, there is enough information there to work it out yourself.

The description on intercepting the IR device describes how to run something before the player, and the pages on the display and audio give sample code for putting something onto the display and playing sound, respectively.

Kim Salo has also posted some code to convert raw images into the proper display format for the empeg. (Kim, may I add your code to the developer site?)

Perhaps someone would be willing to combine all of these pieces and submit them to the developer site as a single solution.

-v