You could buy one of these monsters: http://www.crunchgear.com/2010/04/14/leaked-gigabyte-motherboard-has-seven-pci-e-x16-slots/ Seven PCI-E x16 slots! What do you cool it with? A wind tunnel?
Wow! That's over the top. I'd seen 6 before... but what do you do with 7? Hell, what do you do with 6? The only(?) cards made for x16 are video cards. And you know, x1 cards might not run in any of them... :>) $500 for a mobo alone? No problemo! You CAN run 8-10 monitors if you wish... but not with no "$40 mobo"... (Well, MAYBE you can... but only from the PCI bus.)