Glad if it helps towards puppy in the audio department..
The Qtractor post I found a while back was:
Qtractor graphics becomes very slow with many items
http://www.rncbc.org/drupal/node/441
It's certainly going to cause problems I would say unless you're just recording a few tracks maybe.
Re reading, it seems that rncbc can improve it with pixmap image caching, so all is not lost.
I guess that means having images in ram, so that would fit in with puppy ethos, and keep it snappy.
So not strictly audio latency related, but relevant.
Archpup, a lot of people seem to like it.
Quote "rather than get bogged down trying to compile lots of apps."
I agree, even though I don't compile, I should imagine it can get pretty frustrating if you're trying to trace problems.