Updates!!!
The cab already had a nice monitor mount in it (from the 25" arcade monitor).  So I had to figure out a way to mount a 20" CRT using the existing mount.  It took a few tries but I finally came up with the correct design.  I removed the case from the 20" CRT, attached 4 metal strips to each of the corners, and attached those metal strips to the existing mount.  I was a little nervous at first because it doesn't look very stable, but trust me this monitor isn't going anywhere.  I gave it a few good shakes and it passed my inspection.  It's a "floating" design.....