I opened an account just to reply to this thread because I came up with a way to accomplish this that I am almost positive no one else has thought of.

I have a 2006 E53 with non-DSP and Navigation.

I bought the Dice MediaBridge adapter so I could have Sirius and a connection for my iPhone/iPod.

In order to be able to use Bluetooth instead of having to directly connect my iPhone, I bought a iPod dock to bluetooth adapter on ebay. I could not find any with a reasonable price that shipped from the uS, so I ordered one that shipped from Hong Kong. The only downside of this is that the radio and steering wheel controls will not change the songs. You have to do that from the iPhone, but that doesn't bother me much.

If you want to know what the adapter looks like, go to ebay and search for "iPod dock bluetooth adapter" It literally plugs into the dock cable and becomes a bluetooth receiver.

I routed the Dice cable out through the bottom of the center console panel such that the dock connector is sticking out on the floor between the driver's seat and the center console. This allowed me to plug the adapter in there and still access it in order to unplug it if I needed to in the future, but I have never had to.

If anyone cares, I'll try to take some pictures and post them later.