Well... some news incoming
I'm currently using a Radeon 9600 Pro to drive my two cabs.
Dualhead works, as long as your card detects both displays (you MAY need to add 75 Ohm resistors to the RGB lines).
Also some more bugfixes with floating point values. (I really hate that stuff)
onboard geforce cards (tested on an geforce 6150) works fine also.
I'll add some new options on the next release.
first would be "double 15khz" (details below) and "custom" (if you only want to use your own modelines)
'bout "double 15khz"...
there are two ways to get a 15khz resolution to 31khz.
way 1 (the vga way) is drawing each line twice (320x240 on VGA actually is 320x480)
way 2 (my way
) is drawing each frame twice (means 120Hz instead of 60Hz)
lo-res (15khz) on hi-res (31khz) and VGA monitors works nice
looks sweet on hi-res arcade monitors and "larger" presentation beasts
however to use an real VGA monitor you should turn the "focus" poti a bit blurry, else you will have real sharp hardware scanlines.
hacked one line in MAME to have it output each frame twice cause we use the double vertical refresh (means 320x240 @ 120hz)
it works fine without, however you won't be able to sync the speed via tripple buffer.
*EDIT*
double 25khz (512x384) should work also, as most better hi-res and presentation screens support 1024x768 at 60Hz.
we could use 512x768 at 60Hz or 512x384 at 120Hz.