Quad monitor setup?

Simple question maybe someone is running this setup already.

My current situation is that I'm running a single gtx 570. The card currently doesn't support more than two monitors unless running in SLI... Although a cheap budget fix on paper would be to purchase a couple usb to hdmi adapters thus allowing me to run 4 monitors. Is anyone doing this/or know if this is possible before I invest in any additional hardware?

http://www.newegg.com/Product/Product.aspx?Item=N82E16812119460


Current game Diablo III.

[MiRai]

I'm not sure that adapter is going to give you the gaming performance you are expecting. Don't they render via software?

Hmm. You're right according to reviews it's not very practical for video/gaming. May just as well get a second 570 unless there is a similar device that's beefier.