Foxconn technical support finally came through, and sent me Beta BIOS S02 for the troubled A79A-S. This finally allows memory to run at 1066MHz, albeit with greatly increased timings, well above the speed that the memory is capable of.
In addition, selecting any of the BIOS memory options which would previously hard-lock the machine until the CMOS was reset or the battery removed now simply corrupt the CMOS. This does mean that these options are still unusable, but at least you don’t have to crack open your case to discover this.
HD Audio does work in Windows unless the “NP NB-SB VC1 Traffic Support” option is enabled, when every flavour of Windows (XP SP2, XP SP3, Vista, Windows Server 2008 with Audio enabled) freezes on login.
USB keyboards of all variety still randomly aren’t initialised correctly on about one boot in three, and remain unusable in spite of repeated unplug/replug cycles using different on-board/off-board sockets until a reboot.
In short, better – but there’s still a very long way to go before I’d consider this board suitable for sale to even the technically-savvy general public.