I bought one of these weird USB bluetooth audio adapters that only acts as a bluetooth audio transmitter, meaning that it doesn't show up as a bluetooth device at all but rather as a USB audio device.
The specific device I got is branded as 1Mii, shows up in X logs with the name TaiYiLian and in lsusb as "Cambridge Silicon Radio, Ltd".
I can't really recommend it. There is no way to select which device to pair with (I believe it picks the device currently in pairing mode with the highest signal strength) and there is a delay every time audio is played before it kicks in (at least on my system).
Another problem is that it shows up as not just a USB audio device, but also two keyboards and these keyboards send keystrokes which causes X to loose focus with no way of regaining it by clicking. The only way I found to get normal keyboard functionality back is to ctrl+alt+F2 into a terminal and then switch back to X. Unfortunately this seems to happen repeatedly, so just having it plugged in before boot doesn't h