Multiple versions of Windows 7 not new to beta build 7025
If you've installed the Windows 7 beta from an iso image using a virtualization app like VMWare, you've seen this screen already. Just like Windows Vista, when you leave the CD key field blank, Windows 7's setup asks you to specify which version you want to install.
Why haven't more people noticed this? For one, the vast majority are recording a DVD and installing from there - and you won't see this screen during a normal install. Those who have seen this probably wanted to play with Ultimate anyways - after all, it's free now and might cost us $400 later.
For now, let's remember that this is Windows 7 Beta. The final release could come in a single version, or there could be twelve. We'll just have to sit tight and see what Microsoft has up its sleeve.