IGN's David Doel recently had a conversation with Harmonix, the development team behind games like Frequency and Guitar Hero. The team proposed a sequel to the fan-favorite Frequency and Amplitude for the PSP, however Sony declined their request. The music game would've been well suited for the PSP, as the excellent gameplay of other music games, like Gitaroo-Man, show.
However, to add insult to injury, it appears that the other music game heading to the PSP, Traxion, has also been canned. This music game from LucasArts was supposed to allow players to import their own songs into the game, a "Frequency-killer," as reported by IGN's nixice. He didn't give a reason, but it's sad to see that the music genre seems to be so neglected on our handheld.