I'm not sure if MAME can do two overlapping layers of artwork yet so, just in case, I've also included the combined bottom screen of Mickey & Donald (in Photoshop, it was as easy as setting the top layer as "Multiply"). Also, you may notice that the top screen doesn't have round corners, this is because we seem to be currently missing "DM.53-S-F", which would be the layer that adds them. Any chances of getting it scanned, please?
I guess I didn't scan it because it was blank, but I see what you are saying about the corners. Here's the scan: www.seanriddle.com/DM-53-S-F.tif It should be easy to vectorize!
