Soyo has updated their website with info on their upcoming P4X400 DRAGON Ultra motherboard. The P4X400 DRAGON Ultra supports the VIA P4X400 chipset, 400/533 FSB, DDR400 memory and AGP 8X.
Update: VR-Zone has a review up on the new VIA P4PB400 board based on the VIA P4X400 chipset and officially supports AGP8X, USB2.0 and comes with the new 8X V-Link Hub architecture. They have compared its performance against the SiS648, Intel 850E, Intel 845G as well as the VIA P4X333. Since it's based on the same technology this review might be interesting for you. Soyo P4X400 DRAGON Ultra
VIA P4PB400 P4X400 Review
Update: VR-Zone has a review up on the new VIA P4PB400 board based on the VIA P4X400 chipset and officially supports AGP8X, USB2.0 and comes with the new 8X V-Link Hub architecture. They have compared its performance against the SiS648, Intel 850E, Intel 845G as well as the VIA P4X333. Since it's based on the same technology this review might be interesting for you. Soyo P4X400 DRAGON Ultra
VIA P4PB400 P4X400 Review