In Lieu of a VCDX Defense, VMware Certification will offer informational sessions at the Tokyo vForum on November 6-7, 2012 followed by a VCDX Prep Boot Camp on November 8th.
Registration for the vForum Tokyo Boot Camp is now open in mylearn:
The certification Team will return to Tokyo in April 2013 for VMware Partner Exchange with plans to offer a VCDX Defense at that time.
Will it be VCDX4 or VCDX5 ?
With regards to the Defense, that has not been decided yet.
The Boot Camps are version agnostic.