What else can I say? Probably the VCDX certification is not for all... it require a lot of time, a lot of experience, some "stress", some travels, is not only a technical exam, it requires a lot of skills.
But complete this path give a lot of satisfactions... and seems that also people that has not pass the last step are in favour of this this kind of path.
PS: sorry for my (bad) english, but it's not my native language
A: There isn't a minum or maximum time. You need experience and you must be already a VCP. Then it can take 1 year (like in my case, for Feb 2009 to Feb 2010) or more or less (I had to wait a lot until the design exam was available).
The last part is the one more time consuming because you have to realize your application and submit some months before the defense.
Q: Is still possible to reach the VCDX3 certification?
A: Yes, but only for few days... The last defense opportunity seems to be the PEX 2011, and the application deadline is the Nov, 22 2010!
Q: It is possible to reach the VCDX4 certification?
A: Not yet! The VCAP-DCD beta period is finished, but the exam is not yet avable. Also for this reason there aren't yet any date for the VCDX4 defense (and PEX 2011 deadline is to close). So first new VCDX4 (from the new path) will probably be avable from Q2 or Q3 of 2011.
But VCDX3 that have passed the DCD beta exam will become the first VCDX4.
Q: What about VCDX5 certification?
A: Probably it will take more time, VCDX4 was announced on May, 2010... about one year late the release of vSphere products. Actually the new vSphere beta period has started (to be honest is near to start at the end of Nov, 2010). Actually is not clear it this will be the new 5.x series (maybe it could remain a 4.5)... So until a new 5.x product is not released (with the VCP5 certification), is quite difficult to talk of think about VCDX5
Q: You must be a "master" of big environments to become a VCDX?
A: Really not... You must be able to design a good and complete solution. This sentence of Duncan's blog is very clear about it: "Show you can design for large scale. It’s OK if your actual project was for a small environment, but show that you can think big too."
Q: You must be an active member of the VMware community to become a VCDX?
A: There isn't a correlation... Some VCDX do not partecipate to the community, but can be really usefull partecipate to learn more (and of course to help other community people).
Q: You must be an active blogger to become a VCDX?
A: There isn't a correlation... Several VCDXs are famous bloggers. But other famous bloggers are not VCDX...
Panel is fair-minded with candidated...
Q: You must be active on twitter to become a VCDX?
A: There isn't a correlation... But in the last period more information are on twitter rather than on community... so start follow some right people