I thought if you SLI'd 2 cards,you could still plug ino the secondary monitor and tweak a couple settings to have the 3rd monitor,i've seen 3 monitor gaming computers soo...
EDIT:Read somewhere that you can have like 2 monitors hooked up to one,and then add a PCI card and hook the 3rd up to it,but since he's using it for gaming..that'll be tough with a PCI card,tell him he should stick with 2 monitors that are like,huge.
EDIT 2:Okay heres my last idea,use a mobo with integrated graphics and SLI since he's a heavy gamer,use the 2 slots on one of hte SLI cards and voila 2 monitors,use the integrated card for the 3rd monitor,this way you have a decent card for the 3rd even though its integrated,he should have alot of memory so the amount it takes doesn't make his memory suffer.
