Yeah, unfortunately, this is where Apple has the upper hand because everything currently is tailored to Apple stuff. I am shock that '12 Ford Sync does not work with Android however. I wonder if the new Toyota Entune system will be better with GNex??
When i had my Epic 4G, i tried everything known to men to make the USB connection play music in my Prius...no go. At least with Epic 4G, there was USB storage mode. I even bought "Melodycan" which converts all music to whatever Apple uses. This was the best solution at the time because i can actually listen to ALL my music via USB with my Android phone. My Toyota NAVI actually recognized the songs on my Android phone! The problem was that i had no playlist...and that was a royal pain because i had all the songs, but no organization! I eventually junked the whole thing and went back to my Ipod for music.
With the GNex, there is no mass storage mode. So, this makes things even worst than my Epic 4G! BT Audio streaming is your best bet...but, unlike Apple (5.0) which can convey song title and artist via BT Audio streaming, it looks like ICS is still displaying nothing. At least, Android has fixed the annoying frequency issue with BT Audio streaming with Froyo/Gingerbread. On my Epic 4G with Eclair, there was an annoying interference with BT Audio streaming (at least with Toyota BT system) when playing songs. (My current Nexus S 4G is perfect in this regard.)
Good luck. But, my guess is that you either trade in your Honda in the near future or get an aftermarket headunit that will recognize your GNex. But, first of, Samsung/Google needs to fix the USB modes that are currently available...none of the current modes are recognized by apps, much less OEM audio systems!