UPDATE 6/18/04: I added quite a few new panels since the original version was published as well as new layout pictures.  
If nothing else - seeing other people's CP layouts and panels sometimes help me to think of new ideas.  I can't take credit for the ideas in many of these panels - most of the good ideas came from this board!
Some of the additions to the original modular panel include:
 - A converted Logitech wingman "tron" style joystick
 - Small 4 button "diamond" layout panels
 - USB Gamepads as a four-player option
 - A converted PC Analog joystick panel
 - Volume control (Thanks to Oscar's article!)
 - Q-bert joystick,
 - Dual four-way and top-fire joysticks
 - Dual light-guns
Also I added and updated quite a few pictures of alternate layouts you can create with a modular panel.   
http://www.beersmith.com/mame--------------------------------------------------------------------------------------
Old message: 
I started the project in February and finished the basic cabinet in about three weeks.  
About 2-3 weeks ago I converted the control panel to a fully modular panel.  The modular panel provides a lot of flexibility for different games.  I'm pretty happy with the modular panel conversion, and I detailed a lot of the hard parts (mounting system, wiring) on the web page.
Doc