Yeah metamaterials have been around for a while, though the invisibility idea is relatively new. I havent read the paper but I think the microwave invisibility is a good idea simply beacuse its much easier to fool radar than the human eye. Removing aberations from these materials is not easy and making something totaly invisble would require a near perfect job.
i'm sure someone has seen this: http://www.videosift.com/index.php?search=invisible,+clothes&tag=true Here's how it works: http://news.bbc.co.uk/2/2777111.stm And look at this: http://hipforums.com/forums/showthread.php?t=115016&page=2&pp=10