I also have this problem. Actually it is that the Bluetooth connection drops after waking from sleep mode.
I just got of the phone with an Apple Representative. He had me go though some kind of Bluetooth reset by restarting and holding down four keys. It worked for about a minute, until we hung up, and then it was back to "Bluetooth Unavailable" again. Before he hung up, he sounded very unsure that this procedure would really work. He mentioned a deeper sort of reset, or whatever, might be necessary if this did not work. It is a real bummer having to restart the computer all the time recover the Bluetooth connection.
For me, this whole thing started with the mouse not working after waking up from sleep. Eventually the mouse would connect. Then it was the mouse and keyboard losing connection, and eventually restoring their connection. Then is dropped all Bluetooth connections and stated Bluetooth Unavailable. I went through a fix by removing plists. That did not last. Restarting fixes it temporarily, but the connection usually drops after sleeping.
It is disappointing that Apple seems to be ignoring these Bluetooth Connection drops comments. This seems to be a big problem for a lot of people, with the question just being asked in different ways.
