For anyone that's still paying attention to this, I found this new XM Direct adapter. It takes the song info from XM and wraps it up into RDS and sends it out an antenna line (with rf modulated audio as well).

It seems like this might make the job a little easier to get XM interfaced. Out of the box, it will get the song info on the XM display, but you have to use it's included remote to change channels. I'm almost surely going to get one to hook up to my empeg this way (except bypass the line out audio from the xm direct to run that to the amp).

To get a nicer level of integration, someone would just have to code up a way to have some button presses send out some specific serial commands while in tuner mode. Or (more ambitious), make a separate app that handles the channel changing and gets it's display stuff by pulling the RDS info out of the kernel. I'm assuming the song info is on the serial, and if someone wanted to write an app like that, they could just get the song info off the serial and bypass the whole requirement for a tuner. However, since no one's done that yet, I'm trying to simplify.

With this box, it seems like the simplest way to get this to work would be if hijack's ir_translate allowed you to map button codes to arbitrary serial commands. If that could happen, you just flip the empeg into tuner mode and the display stuff is all handled for you, and whatever buttons you've set up on the remote would change the xm channels for you. Anyone know if there's any way to set up ir_translate this way? If not, does anyone have a Mark Lord genie lamp handy they could rub for such a feature request?