There has been no mentionable change to the CPU interface from Palomino to Thoroughbred. So any board that supports Athlon XP now should support the latter as well - as long as the mainboard maker updates the BIOS to handle the new CPU model.
ALi chipset ... I know the ECS K7AMA aka PC-Chips M817 has a Thoroughbred-ready BIOS available.
regards, Peter