Apologies if this has already been posted, but I was searching about on the web and ended up with a couple of thoughts....
I've got an iPod and an empeg, it has got to the point now where I really dislike taking the empeg anywhere because it's just a pain to carry about. And the ipod is cool because you just take it out of the car with you when you leave, instant music on the move.
Given that I've already got an amplifier in my car (because of the empeg) I've had an idea that both the ipod & karma already have a decent player built in and that you could just hook them up to the in car amp and get your music.
Now, the iPod has the accessory protocol (serial port on the headphone/dock connector) that allows you control it, access playlists etc. Does the karma possess such an interface?
This got me thinking about a very basic dummy "UI" unit that talked iPod/karma that allowed selecting of tracks, artists, playlists etc and just used the accessory protocol to control the actual player.
The hardware requirements for the UI would be minimal, processor (ARM7 core, easy debug, cheap, easy to buy in 1 offs, feature rich), serial port, possibly an audio switch (DAB module?) and an LCD or VFD. Maybe a buffer & ADC to read the audio output to display some basic visuals.
We've got a whole load of philips LPC & atmel ARM7SAM64S processors at work, I might try to convince my boss to layout a little board to try this out, I reckon he'll probably go for it as he's got an iPod.
In terms of leaving stuff in the car, all you'd be leaving is the amp (which you currently leave anyway) and the dummy unit (could make it face removable), but the dummy unit should be pretty cheap.
Anyway, that's my random thought for the day!