SOLVED: Graphics card(s) for 6 monitors at 2560x1440

2 nvidia gtx 650 ti's should work, although I need confirmation on this. It would most likely need some adapters.

Well that's the cheapest solution. Of course if you spent like 800$ on graphics cards it would work for sure

I think the best way to go with such a setup is to go with a AMD graphic card that support eyefinity 6 (meaning supporting 6 screens). Readthis threadhttp://www.tomshardware.com/reviews/toxic-hd-7970-eyefinity-6gb,3264-9.html
You will need as mnimum the HD 7870 card but I would recommend the 7970 to be sure you can run all screens in that resolution. You may even need a to have to do a two-cards setup but since it's not for gaming or that sort of stuff I'm not sure. I would google around for earching a bit more about the eyefinity 6 option.

Thanks. Since DisplayPort to DVI Dual-link adapters are active (need USB power) they tend to be expensive (US$60-100) times 6 in this case. Are there cards with 3 DVI Dual-Link 2560x1440 outputs? I would simply use two of them and be done. Am I dreaming?

Or maybe cards with 2 DVI Dual-Link 2560x1440 + One DisplayPort. I would then buy only two DP to DVI-Dual-Link adapters. Makes sense?

The answer to my own question: any double dual-link DVI card PLUS one Nvidia FX 4500 X2 card. The X2 is actually two dual out dual-link DVI cards on one PCIe slot (i.e. 4 outputs at 2560x1600 max each. simultaneously). So I'm typing this in front of my 6 (hex) 27" monitors system each running at 2560x1440 (2 rows of 3 monitors) for a combined desktop of 7680x2880 or more than 21 Mpixels.