There is not motherboard with 2x AGP slots.
You have AGPx2/x4/x8, but that is in reference to the speed, not to the number of AGP slots on the motherboard. (People ring me up about complaining about this "problem" on a regulare basis with me
It you want 4 displays, then I suggest 2 times.
1. Get another computer
2. Get a video card that can support 4 displays. (If they exist in the first place)
BTW, why 4 displays?
2 I can under stand.
3 is hard core
4 starts to get amazing.