I don't know about hyperthreading, but Asus has just announced a new mobo for the P4 using the SiS 648 chipset.
?The P4S8X is the first motherboard to provide AGP 8X and Serial ATA connectors. With the SiS 648 chipset, the ASUS P4S8X supports latest 533MHz front side bus and Pentium 4 processors up to 2.53GHz and beyond. In addition to supporting high-bandwidth DDR 333, unique MuTIOLT technology increases the bus speed between the northbridge and southbridge to 1GB/sec, for enhanced system performance.?