No luck yet... but I haven't looked around either. I just gave up on it and will look into that task again "after" I find a diversity adapter for the radio first. My radio stations are not coming in clearly because I can only use 1 of the antennae cables. I bought a Y-adapter from Sounddomain, but that doesn't fit (2 full size to 1 full size, whereas the 4R has 1 mini and 1 full).
That JVC HU is neat. Nice novelty. But, due to having only those two main circular (directional) buttons, it lacks the versatility of other HU's and you have to press buttons MANY times to get to what you want. That gets really annoying, and the remote doesn't control all the functions either... you would think that it would, considering that the remote has about a billion buttons on it! I'm happy with it though, 8.5 out of 10.