Speaking of DS... its sound hardware is pretty much designed for music: 16 channels, hardware mixing, etc... On the N900 synthesis and mixing has to be done on software side which is slower.

Anyway, I've been planning (read: dreaming of) a music sequencer for the DS. At least, I've been making lots of mock-ups. I've also been dreaming of a complete sequencer+synth on the N900 ever since I heard of it.

FruityLoops 3.56 was the best FL version ever. LMMS is good too, but its interface (especially the song editor) is more similar to the newer ones.

PS. I'd like to see Aldrin running on the N900 too.