Man am I glad to finally hear someone else using Linux with MythTV. It's great news to see iGuidance works with CrossOver, I will have to try this setup. I was thinking about switching to IG, now I can go forward.
Timekiller..You mentioned Myth .20 and a touchscreen, does your theme have a back button to allow you to exit a screen or are you using the remote/keyboard for this?
On the same topic, have you been able to use iGuidance while listening to music?
In my setup, I had to modify the Myth .15 software for touchscreen/mouse, but also added a back button so all navigation is by touchscreen. (I've been thinking about upgrading to .20 in the car, but am concerned about this back feature) Then I had to use a different WM like FluxBox to give task switching. This allowed me to start the GPS program, switch back to Myth, and start MythMusic. I can switch back and forth with the task bar, but a more integrated solution would be nicer. Right now, I use an IR remote to change songs in the background while looking at the GPS program. I have no keyboard attached to the system, so I use an on-screen KB in the task bar. This has been working for about a year and a half now with no problems, but I really want to get away from Win4Lin and Delorme (no touchscreen support).
I was thinking about modifying Myth .20 to get a persistent MythMusic running. With your theme experience (nice theme BTW), have you run into anything allowing mythmusic to remain running even after the screen has been exited? I'm thinking of running it as its own process, but then there's other problems to resolve.