This should be pretty exciting once it's finalized. The chaps at Windows Phone Hacker (site) have been working on a "Folders" solution to Windows Phone, analogous to the fan concept we ran back in July.
The image you see above is purportedly the real deal and not a mockup--those tiles are "dynamically generated". The only issue we're told is that it's a little "clunky" on the setup which is to be expected with this level of homebrew activity. The good news is the device only needs to be unlocked and not the deeper, more difficult interop-unlock, which is a bit tricky to instantiate.
Windows Phone Hacker is looking to release this and was gauging the desire/want for this type of hack. Basically they don't want to invest time in cleaning it up, making it more streamlined if there's no one to use it, which is understandable. We suspect demand will be quite high for this feature, so let them know in comments and via Twitter @wphonehacker.