xlr8yourmac has posted an spec sheet for an upcoming Dual Monitor Matrox G400 Max Graphics Card from Promax.
It's an AGP card so only Sawtooth owners need apply. But, the advantage to this card is clear... with only 3 PCI and 1 AGP slot on your Sawtooth, you must choose your expansion cards wisely. By getting a 2 headed video card, you can run your 2 monitors and still have 3 slots left over -- you do have at least two monitors, don't you?
Another excellent solution is to get a Voodoo 3 PCI card to drive the extra monitor. The Voodoo 3 is both a 3d card and 2d card, providing VGA output.