No, the Rage 128 can't drive two monitors simultaneously. Plus, it doesn't support Quartz Extreme (the acceleration you mentioned earlier). Pretty much anything else will do Quartz Extreme (any ATI Radeon or nVidia AGP video card with 16MB or more of VRAM). To get two displays simultaneously, you need a GeForce4 MX class video card (or better) from nVidia (typically 64MB or more of VRAM - not to complicate things, but the GeForce2 MX with TwinView and 64MB VRAM will do dual monitors) or an ATI Radeon 9000 (Mac Edition) or better. There may be flashed PC Radeons between the 7000 and 9000 that support dual displays, but Apple never shipped one in a PowerMac, and I'm not familiar with their capabilities.

Selecting a resolution (exact Width x Height) and refresh rate is done in the System Preferences. You can't tell the system how many pixels wide the monitor is, you just have to cross your fingers and hope that OS X offers the right combination from built-in settings. If OS X does NOT offer the magic combination, then you'll need to use a tool like DisplayConverterX or SwitchResX to manually specify those settings. It's possible to get just about any HDTV to work with a Mac, but it can be frustrating.

Peace,

Drew