OCWorkBench has a preview of a AMD RD790 based motherboard. One of the interesting things about this chipset is the support for Quad CrossFire.
The AMD RD790 chipset is an improvement over the RD580 or 580X chipset. The major difference is that it supports AM2+ and HT3.0.
In the test, a AMD X2 5000+ and a pair of DDR2-667 is used. The board you see comes with 4 full length PCIe x16 slots. It is fitted with 4 graphics cards. The interesting thing is that CrossFire works even with 4 cards, but performance is not ready for 4 cards to improve the performance. The PCIe slots can be configured to run in 2 by 16 or 4 by 8 in CrossFire mode. The south bridge is still the SB600.
You can check it out over here but most of the photos are pretty blurry.