Thank you so much for designing this!! I have been thinking about designing a similar board for a long time now. This board should be required for all machines with LED retrofits! It turns a headache causing nightmare into something that is actually an improvement over the original bulbs. Hopefully these will be sold in mass soon, so I can actually start playing LED games at shows rather than avoiding them like the plague.
The design I was thinking about would also provide dimmable DC voltage to the GI light too in order to avoid the strobing on the GI lights.
So, you kind of imply that the matrix can be a mix of LEDs and bulbs? Or does it have to be a complete swap out?
Also, a guy down here in Florida is working on fixing the GI circuits by modding the driver board itself to run DC voltage to the LEDs:
http://www.southernpinballforum.com/smf/index.php?topic=1017.0
John