This is an interesting concept developed by Ralf Ackermann…

An external iphone / ipod touch keyboard – using a more “mainstream approach”. The keyboard (it’s a standard Freedom Universal Keyboard) uses the Bluetooth SPP (Serial Port) profile to talk with a Robotech Bluetooth module ( www.tigal.com/product.asp?pid=1124 ). This module is placed in a modified iphone battery sleeve and connected to the iphone serial port. The jailbroken iphone runs veency (a VNC server) and a tiny libvncclient based VNC client for keyboard event injection to whatever application you use.

All schematics and source code to appear on www.ubiqkom.org soon.

More photos here.