Once I had the LCD monitor, I figured out a simple way to mount it into the existing opening.  I was going to clock the monitor 90 degrees clockwise since most of the games I like to play are oriented tall and narrow.  MAME can clock all the games if you wish.  I got real lucky with the size of the opening and size of the LCD monitor and had about 1/2 inch of clearance all the way around the monitor.  I removed the pedestal from the monitor.  I then used angles of sheet metal to rest the monitor on and secured it on lace with a few homemade screw down clamps.   It ended up being much easier to mount the LCD monitor than I anticipated.