Splitting keyboard -> separate tracks?

[lfm]

Thinking about it, maybe it would be even better to be able to define a velocity threshold, below and above which two different tracks/instruments are triggered.

Have a look at Insert Piz Here - forum here and his free collection of vst midi plugins.
Incrediable good use for various such operations.

When playing and apply different expressions, that's how I read your descriptions - consider using either modulation wheel CC#1 or expressions pedal CC#11 events(not all midi keyboards have that). I guess sustain CC#64 is already used. Yet another alternative, use aftertouch if keyboard has that.

A continuous controller like that could with Piz stuff do either smooth level of velocity changes, like a pan operation, or do hard switches on thresholds.

I think velocity is more difficult to play and really get result that you want.

Common in samplers with articulations - switch keys decide which one to play.

[LawrenceF]

Yeah, for any software based sequencer that stuff should be built in, pitch and velocity filters, whether it's with plugins or just built directly into midi or instrument tracks. I'd be really surprised if any of the usual suspects didn't already have it and you'd have to use a third party midi plugin or something for it.