Hmmm - I'm wondering if you could install this - http://www.siegecraft.us/presta/index.php?id_product=44&controller=product&id_lang=1 - and then put bare LEDs in the Pac matrix board. You'd have to LED the whole machine but if you're doing the matrix why not the rest.
Early AM musing - seems too easy might be missing something need coffee and schematics.
viperrwk