There alpha testing was full from what I saw. I did sent a private message a few weeks ago to the guy ray morgan like the thread on there forums suggests here but no response so who knows.
vBulletin 4.0 Alpha and Beta testing - vBulletin Community Forum
I am not expecting a gold release of 4.0 anytime soon. They dont expect the first release alpha till maybe first week of august at the soonest. Then beta would come after that. Your most likely looking at the soonest maybe Christmas or 1st quarter next year so hopefully vbulletin will respond to us in some manner.