This is not real. Well, not real in the sense that you can buy it. But it is real in the sense some people built it, off the back of GH: Aerosmith.
YouTube user CosmoKramer took the standalone title (specifically, the Wii version), installed a Megadeth intro, then dropped 42 playable Megadeth tracks ("written" in the Frets on Fire forums) into the setlist. It's as ambitious as it is amazing.
[via Go Nintendo]