If you're OK with connecting a cable every time you get in the car, you should have a look at the Pioneer AppRadio 2 and ARLiberator. Be sure to check out some of the youtube videos as well.

I almost put this together for myself. I even went as far as buying an AppRadio 2. Ultimately, I decided that I don't want to plug my phone in every time I get in the car (4 times on most days).

Currently, I'm waiting to see if someone can hack the Play Store into the Parrot Asteroid Smart (2-din). Parrot just has to release it first. Hopefully something is announced at CES this week.