i know sparkfun carries mini breadboards. they might be the right size. i was thinking more along the lines of something that plugged into a breadboard... you would have a piece of circuit board that plugged into the center divide on the breadboard. you would have everything except the voltage regulators, and connectors all sitting on one thing. the voltage regulators could be built elsewhere on the board, and the iobridge chip would only need to handle the communications, so less pins would be needed on the iobridge chip. power would come from the power rails.
parallax makes a version of the propellor education kit that is on a breadboard, and it was fairly easy to setup, and works fairly well.
finally, the other benefit would be the costs would be cheaper, and if a user wanted to build a permenant embedded system, the iochip could just be soldered ontop of a pcb or placed in a dip socket.