I highly suggest checkin out
www.ebay.com and just type in "arcade marquee" you can also narrow down your search with the categories on the middle left hand of the screen. I've seen a lot of those mame marquees floating around, so I'm sure you could find one to buy. You could also probably pay someone here to make you a custom marquee for a price of printing/shipping and maybe like 3 dollars more or something.
-CthulhuLuke