Gosh you're so fast on these things. As others have mentioned, hologram concerts have already been done by imaginary character Hatsune Miku. She's even performed in the states to a very large and enthusiastic audience!
I confess that today your video I liked it very much because since you have started singing it is raining in torrents and this means that there will be no drought this summer in my country. Oh really, Wilson, it is maravillosoooooo!!
+Adam Reed the program is actually called Vocaloid... Project Diva was the game series about them.... they did a tour in America last year.... I couldn't get tickets :(. The main singer is called Hatsune Miku... look her name up on Wikipedia, there is tons of info :p