Is there just a Tuner/Amp head unit with line-in?
 

If it's simple and practical then they probably don't make it. Anyway,
I don't want a CD or cassette transport. I want to plug in my mp3
player via a mini-plug when I'm not listening to the radio. I also want
something that isn't a target to thieves. This doesn't seem do be the
direction the industry is going, but I thought somebody here might know
of something.
Robobass