I built this arcade machine over a period of about 2 months. I basically used the Lucid design for the cabinet, a modified xBox to drive the video, and sort of did my own thing with the four person controller box (which is made from xbox controllers interfaced to traditional arcade buttons and joysticks). Most of the time spent on this project was in doing all of the wiring and soldering for both the xbox and the controller box (special thanks and shout out to Mike Stevens for his much appreciated helping hands!).
The modified Xbox inside is running an operating system called "MAME-X". You don't necessarily have to modify an XBox for this project, you can use a cheap old PC too, but the XBox is the best value in my opinion -- high performance, and best of all, boots up instantly. You have to modify the XBox to run MAME-X but it still plays regular X-Box games without any problems which is a nice bonus. All of my MAME games are on the X-Box's hard drive, so its quick and easy to switch between them (you hit the coin and start buttons at the same time to bring up a menu).
If you are interested in building one, here is a complete materials and price list: (note prices were from way back around year 2000, certain things are much cheaper now like old xboxes or even TVs):
$270 JVC 27" component in television (you can definitely go smaller or cheaper here)
$200 XBox [modified] (can get them for well under $100 now)
$70 Arcade Joysticks & buttons from eBay (also available from HappControls.com) [Note that the buttons require a 1 1/8 inch hole, so if you don’t have such a drill bit you must buy one]
$60 Four Mad-Catz XBox controllers
$40 t-molding from EBay, chrome for the control deck, black for the cabinet for professional finished look.
$30 3 4x8' sheets of particle board from Lowes ($10/each)
$20 Misc. soldering supplies, interfaces, and wire from Radio Shack
$16 Plexiglas for bezel around TV and top of control deck
$15 Black Glossy Paint & Polyurethane for mirror finish
$8 WalMart poster kit for marquee (simple color printout on normal paper)
$7 100 Quick Disconnect wire terminators from Lowes, you really need .187 size but I could only find .235 which works with a little crimping however I STRONLY recommend you order the correct size (HappControls.com has them) otherwize they may fall off.
$5 Black marble contact paper for top of control deck (under plexiglas) from WalMart
$3 Spray Adhesive from Lowes, used to stick controller overlays on the contact paper
$3 Epoxy -- opened XBox controllers, wired buttons/joystick to radio shack interfaces, cut hole in top of controller, then glued down the interface to the controller.
The project was more work than I thought it would be, if I had to guess, I would say at least 40 hours? The assembled cabinet is VERY heavy, moving it was a pain.
XBox Mod Info
To do it yourself you need to be comfortable taking things apart and soldering small wires. But you can also buy some pre-made mod chips or a box that is pre-modified. That is definitely the way to go.
For the joysticks I recommend using MadKatz, you can get them cheap from Sam's Club and other places and they are easier to work with than other brands (the original controllers are terrible to work with for this project). You can open them up, and wire each contact (for each button, joystick movement, etc) to an interface plug from radio shack. Arcade buttons and joysticks are wired to a matching interface, and you just plug them together. It isn't that hard, it just takes a lot of time.