Looking at Ultimarc's website, they list this:
LED Harness
many games use Caps/Num/Shift lock LEDs to indicate game functions. Why not add these LEDs to your panel? Includes harness with Red/Green/Yellow LEDs in raised black metal surround. Plugs into I-PAC or J-PAC.
Unfortunately, the 'Mote Info' link doesn't work

Anyone have this harness? What do you use it for? Lighting buttons? Lighting the coin door? Just lights poking out of your control panel?
I like the idea that it plugs right into the iPac, so I don't need another control card, but not really sure what I would use it for.
Thanks!