I have the PVM 20l5 which does 31khz. But then I read somewhere that the picture can have problems-- do you think that's true?
What problems? 20L5 does both 15 and 30. You could also try running Windows at 480p (if at all possible without the low-res-supporting driver and video card). Then use a scanline overlay to essentially create a 240p picture. I haven't done this myself but I've seen someone else do it with a VGA monitor and it looked great.
I would try the Emudriver method. Google the instructions and buy a supported video card (it'll be an old and really cheap card).