I have a USB mini keyboard that works fine, far better than typing on screen:
Solidtek KB-P3100SU (ASK-3100U) Super Mini Keyboard - USB, 4" x 9"
I have tried several kinds of bluetooth keyboards and none have worked. (And still not with Ermine.) I think this is dependent on Google adding HID support for Bluetooth to Android, or on some third party hacking it for us.