You're not going to find 4:3 LCD monitors anymore. The largest I ever saw was 20.1 inches with a 1400 x 1050 native resolution and that was many years ago.
I've seen some people use an LCD/HDTV in a cabinet, but rotated 90 degrees. I guess they hide part of the screen behind the control panel at the bottom, and maybe part of the screen at the top of the cabinet is hidden as well.
I think the idea is that a 24 inch LCD is more than a bit shorter than a 25 inch CRT arcade monitor...
...so by using a larger LCD, rotating it 90 degrees, and blocking part of it out with a bezel or whatever, it will still fit within a normal-sized arcade cabinet but you get a larger usable screen area.
Somewhere in the last year or two, I saw a Galaga (or possibly Galaxian) machine configured this way in an arcade. I think it was a Dave & Busters, but it might have been the Space Mountain arcade in Walt Disney World.
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