Matrox has never been the standard for anything actually. It's a wonder they've managed to survive this long.

Both NVIDIA and ATI have been doing dual head with full resolution support on both heads for years. Both companies have also been doing dual DVI for quite a while (for consumer-prices mainly on the Mac).

ATI's cards (Mac and PC) have supported 1920x1200 digital output with reduced vesa timing for a few product generations.

4 30" Cinema displays, each rotated 90 degrees would make just about the most impressive setup at any price. How you'll get that setup today is another matter.

I'm pretty sure the new ATI X18xx series cards support dual dual-link - but I'm not sure if the specific models supporting that feature are already available in stores.

On the PC front you're going to find a lot of motherboards have a single 16 chanel connector and then a bunch of single channel. Perhaps one 4 channel. At least the motherboards I've seen however, use short connectors for the lesser channels. Apple's new systems, even though they offer 16,4,8,4, have full-length connectors for each slot. This enables you to stick a standard PCIe graphics card into any slot and run it at the maximum speed for that slot (the 16x board will just run slower in a slower slot).

If you're going to go with Dell panels you can get away with 1 PCIe board with dual DVI output and one or two standard PCI boards (with either dual DVI or single DVI). You're not going to be taxing the PCI bus displaying a PDF at that resolution. Your CPU will bog down well before any of the graphics chips even flinch.

My personal recommendation would be to use a previous generation G5 or G4 machine to run this setup. With 1 AGP card providing two digital outputs and two PCI cards providing one each. It will probably be the most economical in the long run and a snap to set up (a few minutes to just connect everything together before turning it all on). Running Mac OS X 10.4.x you'll easily be able to rotate alll the displays. If running 10.3.x only if the three video cards are ATI's will you be able to rotate.

Bruno