Status update and plans update....
I spent some time this weekend going over the plans with a friend who is going to help me build the cabinet. He has the tools and woodworking experience. After we came up with a plan, we left to buy wood and ... bummer ... the lumberyard was closed. So, cutting is delayed one more week and should start this next weekend.
This has given me some time to refine the plans based on the feedback from this forum and my friend's ideas. First, some conclusions:
1. No casters. What's the point? I'm not going to move the cabinet much. I will add levelers.
2. I'm going to stick with the width of the cabinet and the 19" monitor. I'm not going to build a rotating motor. This is my first cab so I want to build something I know will look good and be sturdy. To overcome the issue of a bezel that is too big, I'm going to look into some artwork that can be placed on the bezel as a cool effect.
3. I've replaced my spaced out 1"x2" furring strips with full vertical 2"x2" furring strips. This will make it a lot easier to assemble, will help with screwing without splitting, and shouldn't add too much weight.
4. I'm going to build the whole thing out of 3/4" AC sanded plywood. This will be a nice surface to paint. Using all 3/4" will be heavier than optimizing with some 1/2" but will be simpler to cut and build.
5. I like the idea of smoked plexi for the bezel. Going to see how that looks.
6. Added vent holes up and down the back of the cabinet. Will add some mesh to cover the vents.
7. Will make the control panel removable, either with latches or bolts and nuts.
8. I'm going to keep the keyboard tray for now but may lose it later.
Need some links / advice:
1. Levelers?
2. Control panel wiring: I've read doorbell wiring, ethernet cables and other electrical wiring
3. Gotchas in using car audio speakers
4. Wire/metal mesh to cover air vents
5. Primer and paint - what type?
6. Euro hinge link?
7. I need some kind of flexible rubber piece to go between the admin panel and control panel. There is a small gap there and the control panel lid will hinge open.
8. Marquee mount?
9. Other things I'm forgetting?
Still to do:
* Map out the control panel
* Design the artwork
Here are updated design pics.

Base frame (2"x4"s)

Base with plywood top

Left side with furring strips attached

Left side attached to base

Both sides attached to base

Interior (monitor mount, speaker panel and admin panel) attached to sides

Rear view of interior attached to sides

Exterior attached to sides and base, with vent holes

Rear view of exterior. Note the upper panel will be hinged so that I can access the monitor from the back

Keyboard tray attached to sides (non-structural)

Door attached to sides using Euro hinge and magnet lock (non-structural)

Control panel box (top view)

Control panel box (side view)

Control panel with lid (side view)

Control panel attached to cabinet

Monitor attached to cabinet

Bezel attached to monitor mount