MTV and Harmonix responded the next day and said that their successful product is an apt target for "baseless litigation." They followed that statement up by saying that they "have substantial defenses to this claim and intend to vigorously defend it."
The official case designation is Konami Digital Entertainment Co. v. Harmonix Music Systems Inc., 08cv286, U.S. District Court for the Eastern District of Texas (Marshall).
But where is Konami's competing product? There isn't one. I can't buy some American home version of Guitar Freaks and Drummania. ... So Konami get off your butt and make your own game and then you can sue....
But to me, if Konami wanted to make an issue out of this they should have started by suing when the very first Guitar Hero game came out...