I dont have a link but over at Toms Hardware you can compare different cards in Single and SLI. Two of the top 7000 series cards in SLI still cant match a single 8000 series, its quit an eye opener.
I've got a single BFG 7800GTX thats rapidly becoming 'outdated'

. Instead of spending $200+ on another 7800 for SLI, I'm now better off spending the same amount of money on a single 8000 series card for twice the performance, unbelievable!

SH3 lGraywolves looks much better to me than SH4 1.2 and thats a bummer!
Speaking of 3DMark06, is that an 'accurate' benchmarking tool or is there another better one to check system performance gains or losses?