would my method work as well?
In your diagram you've got a the console->DSUB15 converter plugged into a video amp and then into the DSUB15 connector on the arcade monitor.
If you do have an arcade monitor that has a DSUB15 input (like many modern ones do), there's a good chance you don't need the video amp, as these will either autodetect the right input voltage, or be switchable via the monitor controls (all our multi-res monitors with DSUB15 can switch input voltages as required). So it's just a matter of taking the Ultimarc console adapter's DSUB15 plug and plugging it direct into your monitor.
with the subject brought up, on vacation in florida i went to an arcade and found that many of the games were running off of pc based games/ and or emulation. very sad
Whenever I see this I confront the owners and tell them straight up that it's unacceptable, and report them to whatever authorities are appropriate (here in Australia, it's NAMOA).
I feel for arcade operators with lagging profits in modern times, but breaking the law for profit is not the answer.