The_Blood_Raven :
I disagree, I've gone with dual cards for customers a lot. One had 2 4830s, 2 9600 GTs, and 2 8800 GTS 512mb. It depends on the circumstances.
But, I'm guessing at the time, all of those offered THE BEST bang for the buck, correct? I've done the same thing numerous times.
But, depending on your customer's talents and patience, it's a risk for your tech support time. If it doesn't offer better performance, more often than not, or at least in the specific games important to the customer, going with the single card solution makes more sense IMO. As you already know, dual 4830's are sweet; I'd talk them into that budget if they want to run crossfire. Otherwise knowing they are ready for a second 4850 (if need be) should add value to them.
I'm all for cheap multi gpu solutions that can spank a single GPU for the same budget. Matter of fact many months ago had hoped on doing a budget sli/crossfire article with dual 4850's, 4830, 4670, 3850, 2600XT, 9800GTX, 8800GT, 9600GT, 8800GS, 8800GTS320, and 8600GT with maybe a few high end single cards thrown in for comparison. Super time consuming to do a large game suite, but I wish the idea had gone through as I'd enjoy the hands on testing and more importantly seeing the results.