Ok, Wells Gardner and Betson Imperial each have a single monitor that does more than just standard res. They each have a triple resolution monitor that does Standard Res, Medium Res, and VGA res. So they can take normal VGA (off a computer), standard res (off an original board, or a computer with arcadevga or proper software), or medium res (off anything you can get to output it).
The effective bonus to using that monitor is that it doesn't NEED an arcadevga card, and if you have one then it can still do non-interlaced 640x480. I own one of them. So if you are coming up to buy a cab from me, then you can check it out and see if that is what you want, if so then you can always buy my TMNT cab without the monitor. Also these monitors don't need an isolation transformer, which isn't particularly a big deal, since every real cabinet has one in it anyway.