It was not taken down, you can get to the official beta on the opera site, they just no longer let you directly link to the cab file as you must sign an embargo first.
Anyone who wants to download just go here:
http://www.opera.com/press/reviews/mobile/
go here and type in your name then there will be a link to the official download with some instructions, and its the same link as was posted by the OP, just no more direct linking.