Jacob Haggarty said:
How would one go about gaining himself entry to such a prestigious beta such as the likes of this one...?
Or is it too late?
If you have a battle.net account, you need go into the beta section of it, upload your system's specs via the tool provided, and check some boxes based on the betas you'd like to participate in. This requires you to have at least one game registered under the account, which can be done with a CD-Key entry, assuming you have a physical copy that's gathering dust anyway. Good way to make sure you have a virtual back-up available at any time, too.
The picking for the beta is random chance, though. However, since the release is early next year this thing is likely to last upward of five months or so, so there's really no reason not to opt in.