All you need for that rig now is a (wireless) remote to hit next track etc. and you could leave that huge rig in a bag with the screen off for longer battery life.
Shame you wouldnt be able to adjust volume though

I wonder how the sensetivity of the SA6 and LW compare. Maybe you could cut the plugs off the wireless thingy and replace them with LW plugs. Wouldnt be too well tuned for LW's though I imagine.
I use mine at home so they would be really handy, would deffo buy. Even better if the reciever had a PTH thing in it! Dream for me! Wouldnt really use it with my d2 i dont think, as i would like to change song with something like a remote, however I guess i could just do what i do now, and put the D2 and transmitter in my pocket/blazer and change track through it by holding the tactile menu button, and vol with the vol buttons. Would rather be able to use a remote, and leave it in my bag all day, however i wouldnt swap my D2 just for that!
Matt