It seems that CrossFire, in its current form, is considered by some as a mainstream product rather than a top of the range job. In fact, that's the angle Asus are coming from with their latest motherboard, which Anandtech have reviewed:
When the Asus A8R-MVP landed on our doorstep, we were frankly a bit disappointed. Here was the first Asus board built with the ATI Crossfire AMD chipset and the first board to market that uses the ULi M1575 south bridge instead. If you recall from our launch review of the M1575, this ULi south bridge fully supports SATA2 and provides competitive USB performance - removing the few nagging issues with the excellent ATI Crossfire AMD chipset.

So, why were we disappointed? We really hoped that Asus would deliver a super high-end board, much like the Asus A8N32-SLI deluxe 8-phase that we recently reviewed. That kind of board could clearly show what the Crossfire AMD chipset was really capable of doing. Instead, we had a competent-appearing mainstream board that will likely sell in the $100 to $125 price range. Our first thoughts, naturally, were "ho-hum", a solid but unspectacular Crossfire AMD.

We even talked with Asus about why they didn't lavish their attentions on the A8R-MVP, and we were given perfectly reasonable explanations. With Dual x16 NVIDIA now available, Asus really believed that the ATI Crossfire AMD was better positioned as a mainstream product, and Asus would likely give "top-end treatment" to the upcoming RD580 ATI Dual x16 Crossfire chipset for AMD. We couldn't argue with the Asus logic, but it did not stop our disappointment that maybe this board could have had it all for those looking for an ATI chipset solution for Athlon 64 Socket 939.
[Anandtech]