Thanks for comments!
The vinyl worked very well on this project, I'm glad I went that way. One of the concessions I had to make for this cab to be placed in the 2nd living room was that "it couldn't have any stickers or characters all over it" (as she put it...).

So instead I used the black vinyl under the glass top instead of an underlay. It looks okay, I guess, but I would still have rather made a Ms.Pac/Galaga themed underlay. I'm patient, though, I know I can wear her down in time...
The write-up was a bit light in terms of the cabinet hardware/software config. Here's how I have it set up:
Hardware
AMD K6-2 500
192MB ram
ArcadeVGA
SB Pro (ISA) - still the best soundcard for MAME, especially in DOS!
Software
Win98SE - booting into DOS mode
Gamelauncher (rotated for vertical monitor)
DOS MAME .70
I used DOS because I don't have (or need) a keyboard/mouse on this cabinet. When I'm done playing, I just exit GL and shutdown the cabinet with the switch. I've heard speculation that recent builds of DOS MAME have included fixes for the auto-res, but whatever MAMEDEV did or included, it works great now! Every vertical game I've tried comes up perfect, no fiddling at all with the monitor or software resolution settings, and I get a perfectly filled screen every time. I don't have all that many games on this cabinet. My game list consists of the Pac's & Galaxian/Galaga ones, Mr Do & Mr Do's Castle, Donkey Kong, Time Pilot, 1942, and a other classic vertical games. I altered JoyMonkey's VMOVER batch file (
http://mame.joymonkey.com) to copy over all the vertical games from my upright cabinet across my network into this cabinet, then I scanned through the remaining games and only kept those with two buttons or less. Thanks to JoyMonkey for the batch file, it worked great! I was skeptical on how well the 8-way games would play with the 4-way Ms.Pac/Galaga sticks, but so far they seem to be working fine. I can't hardly tell I'm using a 4-way stick with games like Time Pilot and Gaplus.
rampy - I covered the bottom of the power supply with this type of velcro tape. It's probably the most securely attached component in the cabinet!
http://www.staples.com/Catalog/Browse/Sku.asp?PageType=1&Sku=460962