Okay, so I bought the Griffin Autopilot
today and it does indeed work. It charges my iPhone 3G, music plays through the dock port just like my old Belkin, and as an added bonus those buttons on it work for song selection, way better than trying to use the touchscreen while driving (dangerous! I used to do that with my Touch and the Belkin, I'm a moron 0
I do get the incompatible message when I plug it in though. Its the same one I get with my Sony iPod home theater dock where it says it may cause "interference" and that I should turn on airplane mode. I just say no and haven't heard any weird interference, then again I don't get many calls, so maybe I would if someone tried to call.
This is the closest I've found to a working replacement for the Belkin Auto kit. I've got 30 days to take it back, so I'll report back if I notice anything else weird about it. Otherwise so far so good!