Yup. I can testify that thanks to this little tip from Conner_Bw, I now have a “built-in” realtime timestretch function in Renoise and was able to ditch using Ableton Live for that purpose. All I have to do is loop a sample, check Sync in Sample Properties and fire up AUPitch and tweak the pitch to taste, which is exactly what I wanted.
For non-OS X users, we also have the rubberband lua tools in 2.6 like
http://tools.renoise.com/tools/rubberband-timestretchpitch-shift
and
the latter of which can apply timestretch/pitch-shift to only a selection of a sample, from what I understand.
For general use, I’m really enjoying the sample sync + AUPitch method and find it the easiest to use.