just got myself a Matrox M9140 LP, with 4 DVI outputs. 4 x 1920x1200 (!!!). the only one i found with this resolution for quad monitor... and it's not really expensive... i've attached 4 24' screens to it... works great. way good enough for trading, for gaming it might be a bit too slow, don't know, it has only 512MB. i feel like being more than busy with 4x24' (equal to 6x19'), maybe i could handle 6x24' (running tv)but definitely not much more without loosing orientation.
quick solution to the present problem, and prevention for future problem: buy another computer for the boys.
Yep, i know the obvious answer is buy another computer. However, i just want to get a card, that will support two monitors, with about the same amount of grunt as the 9500GT, but in an ati format.
You're probably going to have to do it by trial-and-error. ATI is not in the "multi-card" business, so doesn't bother to try to make it so that its cards will play nice with others. There are some cards using ATI graphics engines which will work together, but may not include your cards. It's probably going to cost you too much to "buy, try, return" various cards... if I were you, I'd stop the process and pursue something which is known to work. Best hope is get another of the very same card you're presently using.