http://www.gatewayelex.com (800-669-5810) has cold cathode fluorescent tubes in various lengths and colors. (they call them clip board illuminators?!!!)
i do not know if they show on the web site, but the store in San Diego has them in stock.
the i-o needs one with 8" illumination length, 8.75" max length with one wire 11" and the other wire 2.75".
you may need to change the connector with the connector in the i-o,
you may need to extend the wires by splicing in the i-o wires.
just watch how the i-o display comes apart so you can get it all back together.