In absence of a timeline system like the one i used to work with in flstudio, i find myself jamming and improvising a lot. More ad hoc (per patch) systems of storing patterns and short bassline, in the style hardoff is talking about i guess. I'm currently more thinking about making patches that manipulate combinations of other patches.
However, before discovering pd, i'd always been looking for ways to perform live with the computer. I made hundreds of songs in flstudio, but when it came to performing them live, it felt like i could just as well put on a pre-recorded cd of my tracks, whereas improvising with my self-built pd instruments and fx make me feel more of a musician instead of some kind of half-dj.
Oh well, that's maybe not really an answer to your question of course. I've already tried a couple of times to make a polyphonic keyboard recorder, and always realize at some point that this is not really the strong point of pd (but i could be totally wrong of course). It seems to me that if you're looking at a timeline system, it could be a better option to look outside pd and link that to your pd stuff. Just like the iannix project, which looks interesting enough.
Just my 5 cents of course,
Domien