Beta 1 is all about Windows 7 compatibility. Beta 2 is where new things show up for XP/Vista users
I understand there was an impulse issue which is why the build went away, hopefully that can be sorted today and it will be put back up.
If you do encounter older skins that have issues on Windows 7, please let us know so we can investigate if there is a way to improve them.
BTW the Leo skin has some new taskbar buttons in Windows 7 (mouseover them), and Diamond and Aero Metal are showing off the Windows 7 resizing startmenu.
RedneckDude: It should have worked on Windows Vista just fine (it uses the same files as Windows 7)