Wow. You guys are great. Lots of ideas here.
I've been brooding over the "dissable, measure, Visio-based-on-measurements" plan. My worries have been simple:
While I spend weeks doing the (correctly placed) artwork, the damn CP remains disassembled and I can't play the machine. I think that's why I've been dragging my feet anyway. The worry that someone will come visit and want to play just after I've taken it apart...
it's really cool, trust me. You can't play it, but if you could, you'd be impressed. Of course it works! No I'm not making this up! Yes, M-A-M-E. Oh forget it!Or I'll start jonesing for Robotron right after dissassembly. So I was hoping for an idea that would allow me to do the artwork while the CP remained assembled. I think that's just my latent laziness coming to the surface.
So now I'm really digging Gunstar's "drill new holes!" idea. I had not thought of that for some reason. I have lots of extra MDF anyway, I can rework the layout a bit without touching my original CP (which I can still play!), I can switch to 1/2" so that I don't have to figure out the whole 3/4" plus lexan plus t-molding thing. This is a great idea. Except that I cannot easily start from my existing CP layout because I still don't have the measurements!

But I can measure off the assembled board accurately enough to get started. And I can fix some of the little things I don't like in my existing CP. And I can take my time now and not mess with the playable machine until I'm ready to move the controls over.
I also like the disassemble and measure plan. I have both Visio and Illustrator and lots of artwork ideas. Drawback is having no CP during the detailed design stage.
And I like FractalWalk's grid idea too.
I like 'em all. But I think I'm going with "drill new holes". How'd I get so attached to a 21" bit of holey wood in the first place?!

Thanks guys!
- pmc