OP - you could try a different brand of card that is build for that?
I run a Matrox G450 quad card... I can get up to 5 monitors, 4 on the card and 1 on the motherboard. We also run dual quads to get up to 8 monitors. The Matrox cards aren't cheap - but they are built for what we do, rather than gaming. They are a little loud (air cooled) and a little expensive, but worth EVERY penny of them.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814106001
Sorry my suggestion doesn't offer a solution without buying new cards. These Matrox cards really work though... We buy for about $500 each - PM me if you are interested.
I run a Matrox G450 quad card... I can get up to 5 monitors, 4 on the card and 1 on the motherboard. We also run dual quads to get up to 8 monitors. The Matrox cards aren't cheap - but they are built for what we do, rather than gaming. They are a little loud (air cooled) and a little expensive, but worth EVERY penny of them.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814106001
Sorry my suggestion doesn't offer a solution without buying new cards. These Matrox cards really work though... We buy for about $500 each - PM me if you are interested.