I Dunno seems to me alot of the functionality you seek could be achieved by using apps like Custom Car home or Car Dock Home V3 with shortcuts to Youtube, Navigation etc. Those dock apps act as a front end to make it easy to access the apps you want in the car! Then pair it with the Tasker app and automate some task to suit your needs. As far as Radio is concerned i use apps like Tune In, Last.fm, Pandora,TinyShark ( a Grooveshark client) and Slacker Radio for my streaming music needs. However my Tablet is connected via Bluetooth to my stock head unit that has a2dp streaming so control is easier in that regard. Personally i like DoubleTwist because it has an addon called Airsync that allows you to update your song library wirelessly over wifi. That program also has an Itunes like appearance and allows you to sync and organize your songs. If you want to check out my install it's Here
Whenever you complete or would like to show off your Android Car Install or worklog feel free to post it at http://www.android-car.com/Show-Off-Your-Ride.html Just starting out and would like to create a community based just on Android in the car.
Hope my tips were helpful, Good luck with your install! As For me Android is the way to go as for my car infotainment needs!