Well as I said, they're all done except for the pointer.
Right now, the machine boots up, goes to the custom bootscreen, finishes, resolution changes, pointer shows up (black background throughout), then mamewah opens. No icons, no weird background colors, no dialogues, etc.
If it weren't for the pointer, you'd never really know (well the boot screen linked does say MameXP, but that's about it). Just looking for a way to deal with the pointer.
It seems like custom pointer schemes are not immediately loaded, either. I was thinking I could make a pointer set full of blank cursors(and just switch to another theme when I needed to), but I changed to a non-standard scheme and found that there were several seconds when I had a pointer onscreen, but the scheme had not yet taken effect. So, a custom scheme with blank pointers would still not do the trick (you'd still get a few seconds of normal cursor before they disappeared).