I don't seem to have found others with this same problem. I just purchased an N800 and immediately flashed to OS2008 (2.2007.51-3).

I now just got a Stowaway bluetooth keyboard. I've been able to pair it successfully (using all the wonderful help in this forum). But, when I use the keyboard the following happens:
the bluetooth icon turns blue
the blue LED on the N800 flashes 3 times
the N800 reboots

The behaviour is quite consistent.

Any places where this newbie can start to look?

TIA!

Fixed it. It was related to a change I made for x11vnc.

According to:
http://maemo.org/community/wiki/how_...800_from_a_pc/
in order to access the top left "start menu" when remotely driving my n800 via x11vnc, I had to add the option "-extension XInputExtension" to the end of the ARGS="...." string in the file /etc/init.d/x-server

When I removed this modification, the BTKB now pairs up perfectly without causing a reboot.

I'm just now waiting for my USB adapter to plug in my mouse (and when will Abiword be ported to OS2008).