It's not exactly the same as you are suggesting, but I think it would be amazing to have a wireless 2 x phono output, such that when DJing from the n900, you could plug that device in to the mixing desk and DJ (ideally with headphones) from the n900 without having to be right next to the desk.

That would also work for controlling home sound systems in the same way. I don't need ijack, just audio out

Ben