8KTA2 has the 686B, and my guess is that many others will switch over during the next few weeks ... the 686A and B are pin compatible, and it just takes a minor BIOS update to support UDMA100 on the B revision (much similar to the situation when the 596A was updated to 596B for UDMA66).
Some manufacturers announce the switch (Chaintech, PC-Chips, Epox), some others have no mention of it but offer BIOS updates that say "Added 686B support" ...
Same btw for any other board type that uses the 686A, be it socket-370, slot-1, slot-A or even super-7.
Regards, Peter