Hmmmmm, after looking at this a bit more maraxle, I think that this addition to my cab probally wont happen. Its looks a bit tricky and beonnd me.
Ive only really dont script programming (javascript, actionscript, ect) and the last time I did that, it was 2 years ago.
How do you send the info in the text file to the screen exactlly? How does it interface with MAME or your frontend?
I can probally come up with a zillion more questions. I recentally got a 15" monocrome LCD screen, that comes with its own special ISA card(for free

).
I was thinking of doing something like your idea with the text files, but either send text to it or a picture, like a pic of the origonal overlay or a generic pic just showing which button does what.
If you can understand my idea & can possibly help, please PM me, thanks in advance.