Eric Sloof just posted that a beta of the Design Exam, which is part of the VCDX Certification, is available as of now.

VMware is pleased to announce the availability of the Design Exam (beta).  I can take the exam at Pearson VUE Professional Centers in London, Frankfurt, Paris and Madrid. Only individuals who have successfully passed the Enterprise Administration Exam and have been authorized by VMware will be able to register to take this exam.  The exam is four (4) hours in length to allow time for candidates to comment on each item. My comments are invaluable in improving the overall exam.

I already did the exam a couple of months ago when it wasn’t even Beta yet(Yes, I passed the Enterprise Exam Jason, but I haven’t received my score for the Design exam yet). I used the following documents to prepare for the exams, both Design and Enterprise, but because I didn’t had much time to prepare I mainly focused on the Enterprise exam:

In my opinion the Design exam is tougher than the Enterprise exam, but I did both exams on the same day and I didn’t know what to expect from the Design exam. I would also suggest that besides reading the articles above you also dig into the different type of designs and the phases etc. Good luck!