Aaron Lindsay and Kevin Dodge, rather than just writing wistful blog posts about the defunct series, have created a homebrew "tribute" to Amplitude on the Wii. Supersonic Wii: Winter Edition, submitted to the Drunkencoders Winter Compo, is a pretty accurate imitation of Amplitude, right down to the typeface. In Supersonic, as in Amplitude, various instruments in a song correspond to "tracks" on the game field, and players must complete measures on each track, quickly jumping from track to track to maintain combos.
The game features nine songs, and is totally free! Provided you can run Wii homebrew, of course. If not, there's potentially some cost involved with the setup. Check after the break for gameplay footage!