Our friend and LiveSide reader Gilly2468 over at My Microsoft Life has come across a Windows Live url complete with a partially working Wave 4 Header. The url, https://consent.live.com, which appears to be available to anyone with a working Live ID, contains the Wave 4 Header:
While you can poke around the drop down menus, and actually sign in and use the new Web Messenger, most of the links either don’t work or resolve back to existing Wave 3 pages. Still, if you want to check out live what we’ve been showing you about the new header for a while now (amazing the stuff you can find if you know where to poke around!), you can check it out for yourself.
Edit: Thanks to comments from Andrew, Lo spazio di Ugosan and Brammie2118, Microsoft have reverted the consent.live.com site back to the old Wave 3 header. However, going to https://consent.live.com/pp800/manageconsent.aspx will still give you to Wave 4 header.