Another option might be to use a card with DVI output with a good quality DAC to generate the analogue signal needed to feed the CRT monitor.
That would remove the pressure from trying to source an ATI or Matrox card, that generally have a well implemented analogue section.
A Geforce FX 5900 or even a 7900GS, for example, then becomes an option without needing to be picky about a specific card's native VGA output quality .
Another option is to get a workstation class card (Quadro or FireGL) as these are usually built to a higher quality standard. However, I suspect that, by the end days of analogue VGA's mainstream popularity, even workstation cards were mostly expected to be used over DVI, so analogue output quality might have become more of an afterthought.