I just had the same problem.
Status just changed to "not available" all of a sudden.
I had to reboot to get it to come back. My BT was already off to begin with.
Something else which might/not be related are things plugged into my USB and/or FW ports that cause my machine to freeze up. I can only get the machine to restart by holding the power button down until it shuts off. If I don't pull the devices (external FW HD, and a USB drive and mouse) out, my machine won't boot back up. It will freeze at the white screen and the gray apple logo never appears. I have to force shut it down again, pull anything in the USB and FW ports and turn it back on for it to boot up.
I have done a verify and repair as well as a permissions repair to no avail. This has happened a few times now. Seems either the drivers are corrupt or something else screws with it every now and then. Whatever it is might be messing with the bluetooth now.