I had the privilege of being at MW Expo SF last week, and got the chance to speak with Eric Zelenka, Apple's Product Line Manager for Server Software. I asked him about getting a beta of 2, and he said they already had enough beta testers. It didn't sound like obtaining a beta was do-able, at least not for me. For those who are part of Apple's beta program for server software, it sounded like they already had gotten a copy.
Another member of Apple's server software engineering team told me to look for a release in April, which floored me. I assumed it would be months after the March 24 release date, but he said no, that schools would need time to test and implement before the fall.
With that in mind, they are farther along in the development cycle than I realized, and getting a beta may be nearly impossible through official channels.