Okay, thread back from the dead...
Chose an AN8-Ultra and everything went smoothly. Recognized my Opteron no sweat (board shipped with BIOS 15) and didn't require any BIOS tinkering to get up and running. To the couple of posters asking about temps...I don't know about the earlier production, but the board I have runs cool. I have the stock HSF, single 120mm PSU fan, and a single 120mm (7volted) exhaust case fan. Air is sucked in over the OTES radiator by case pressure and no part of the system is too hot to touch (my highly scientific heat testing.)
The only problem I had was that my SI-97 heatsink doesn't fit, and it's supposed to! So if anyone is using the AN8-Ultra and would like to chime in with [whatever heatsink] they are succefully using, it would be greatly appreciated.