PS: In my bedroom I've been using a Motorola DC800 BT transmitter (RCA input) with the Motorola S705 BT pendant which I plug my own headphones into, and it's worked well to watch TV without bothering the wife. So that's another option, although I think I'll be using the XP400 more when it arrives.
One issue I have with my current setup is that when I feed the S705 pendant into a nicer amp then I get a little too much noise to enjoy it if I leave the charger plugged into the pendant (ground loop, etc). Unplugged I the battery lasts long enough to watch TV for hours, but I often forget to plug it back in. In addition, the output of the BT S705 pendant isn't really high enough to use as a preamp to feed into another amp, unless you like to cramp up the nicer amp to make up for low source voltage. Unfortunately I often forget to turn the amp volume back down and when I switch to another source I get blasted.
You can use the DC800 transmitter with any BT headset and it can act as a receiver too, so you could use two of the DC800 and feed the thing into a nicer amp (bypassing the BT pendant). The DC800 uses a std mini-USB charger like the BT pendant.