Ultimarc, the Ultimate in Arcade Controls.

The Ultimate Video card for gaming on 15Khz Arcade Monitors and now PC Monitors
Vista 32WDDM drivers now available (email for details)
YES NOW ALSO FOR PC MONITORS!
TRY CLASSIC GAMES IN THEIR NATIVE RESOLUTIONS ON A PC SVGA MONITOR IN WINDOWS!
INCLUDES CRT AND LCD (DVI) DIGITAL MONITORS.

Now also supports 25Khz resolutions on multi-frequency monitors.

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Connect your 15Khz arcade cabinet monitor to your PC with NO special configuration or special driver software in either DOS or Windows.
Now you can also connect an ordinary PC monitor and get all the resolutions of the 15Khz monitor plus conventional higher Windows resolutions.

Displays all boot, DOS and Windows screens on the arcade monitor and/or PC monitor. Displays Windows desktop in a choice of resolutions including interlaced and non-interlaced.
Connect an ordinary PC monitor, or an arcade monitor, or both at the same time
Allows DOS MAME or MAME32 to run almost all games at their native resolutions without hardware stretching, scan converters or other degradation.
All the native game resolutions are available on bith the arcade and the PC monitor.
Emulates the original game board's graphics hardware closer than has ever been possible before.
Contains 28 built-in 15Khz video graphics modes tailored specially for emulation. All of these modes also available on a PC monitor.
Now supports 25Khz modes as well, on multi-frequency monitors such as the WG D9200.
All 240-line modes have an exact 60Hz vertical refresh rate for best performance in scrolling games.
Special 300 X 256 Mode timed at 53Hz vertical for games such as Mortal Kombat .
When used with arcade monitor, all video modes timed at 15.7 Khz horizontal frequency to eliminate picture shifting on mode changes.
Also contains all standard VGA graphics and text modes, running at 15Khz. On arcade monitors. text screens display the full 25 lines without interlace using a special reduced-height font.
All special modes available in Windows XP, Windows 2000 at all colour depths. NOTE Windows 98 is not supported. Vista 32 bit Beta drivers now available.
Desktop rotation supported in Windows for vertically-mounted monitors in Windows XP and 2000.
Choice of Windows desktop resolutions including interlaced and non-interlaced modes. Can be assigned hot-keys .
Virtual-desktop mode supported in XP, 2000 and Vista, so you can run a desktop of 1024 X 768 and auto-pan.
No MAME monitor configuration necessary, no need even to tell MAME you have an arcade monitor.
Run any Windows application which can use 640X480 or 800X600 on your arcade monitor including 3D games.
On PC monitors, all the native game resolutions are available, plus conventional Windows resolutions.
All modes locked with vertical and horizontal negative sync for easy connection via a direct cable.
Choice of available connection methods, Via J-PAC, Via Video Amp, or Direct Cable connect.
Powerful ATI Radeon 9250 AGP or Radeon HD2400 PCIe chipset for great performance in 3D games as well as emulation
.Get the best from your D9200 or Betson multi-frequency monitor. The ArcadeVGA card will run the low frequency modes which these monitors can handle, as well as the higher VGA modes.

So, what exactly is the difference in quality when using a PC monitor between the ArcadeVGA running at the native resolution and an ordinary card running Direct 3D stretching?
The difference actually depends on what types of games you play. The most striking improvement is with older, classic games which have "graphics ROM" type character sprites such as Galaga, Pacman, Space Invaders and the like. The difference is clear.
Pictorial graphics of later games show an improvement in sharpness with no loss of detail, giving a picture where you can see each individual pixel of the original. On this type of game it is a matter of taste as to whether you prefer this level of sharpness against a Direct3D picture which slightly blurs and softens the edges.

The picture below shows Ms Pacman running with Direct 3D enabled, auto resolution.

This picture shows the same game with a fixed resolution of 352 X 288. No stretch nor Direct 3D
Ms Pacman Native Resolution