A reliable source has provided us with a whole batch of photos showing an upcoming Lynnfield motherboard from Asus. The Maximus III Formula features a P55 chipset, and it looks to be part of Asus' high-end Republic of Gamers series.
A look at the PCB reveals three physical PCI Express x16 slots, at least nine Serial ATA ports, some fancy-looking passive coolers, and integrated buttons to start up the system, reboot, and clear BIOS settings. Asus has also implemented its MemOK! feature, which is meant to cycle through memory profiles to get a system to boot with unsupported RAM.
Based on what we heard at Computex earlier this month, motherboards like these should come out alongside Lynnfield processors in late August or early September. Many P55 boards should be cheaper than current X58 offerings, although you can probably expect this particular model to carry a price premium.