Hi Big K,
1) Already available Check out the Hamburg MP57 radio from Blaupunkt in market.
2) I am pretty sure about ipod, but what is zune ???
3) Really crazy - i can say that for radio stations that support RDS/RBDS, you can search and play stations based on genre (like classical, news, rock, etc). but regarding mp3 songs, browsing based on the id3 tag (which includes the genre) should also be possible. but choosing something automatically seems like AI which is too much for a car radio.
Anyway let the ideas flow !!!!
Karthik