I wonder who did it, though. This looks like someone has done a pretty good job in recreating even tiny details, something like this could definitely be worth money when sold as an “add-on”.

I would like to point out, though, that creating a skin for an operating system that makes it look like another one is hardly illegal. There are millions of OS X skins for Windows XP etc. without any legal issues, so why not do the same on a mobile phone. Don’t they always say imitation is the highest form of flattery ;-)