1) Add a second video card. This will have to be a Mac card compatible with your particular machine
2) Accept the compromises and go with one of the Matrox Dual or TripleHead2Go products
I now have a new Mac Pro running 3 Sony 23" CRTs.
Close... it is specially reinforced as they weigh about 100-lbs each and that does not count the video monitors an light box!THREE 23" CRTs?! Is your desk made of I-beams?!