I've been working on this project a while before discovering this forum, but the really interesting stuff has only happened recently.
From the very start of deciding I want an arcade cabinet I challenged myself with a rule: little to no out of pocket cost.
So my first cabinet was a generic design:

PS3 controllers, PC trackball, and monstrously heavy 3/4th inch MDF. Also very ugly. However everything was procured for no money out of pocket. Mostly parts exchanged for working on PCs.
So after discovering a local amusement company's cache of discarded cabs (all in some state of disrepair) I started pulling components to put together something with more respectable controls, and a more family room friendly design:
Thus was born the Armoircade:

The control panel sources buttons and joysticks from derelict WWF Wrestlefest and Marvel Vs Capcom panels (never found the rest of the cabs). A Happ 3" trackball from a Golden Tee cab, and an odd little three-in-one button from a slot-machine type game:

The base of the CP is a scrap bit of 1/8th aluminum. I haven't decided on how to finish the aluminum though. I'm thinking a solid color will probably blend into the overall look better than a more traditionally designed overlay.
The entire CP slides out like a drawer and locks into place with pins on either side. A small shelf behind the controls will have room for a keyboard and two cut out holsters for dual light guns. The holes in the front are for the speakers.
The monitor is a decased 21" Hitachi VGA CRT:

So far none of the wood working has begun, as I've been tweaking the design. Another goal with this layout was to fit the machine into the smallest possible footprint. Currently it's planned to be roughly 25"x26"x60".
I'll have actual pictures once some wood gets cut.