The GrainStretch.ens is a Reaktor patch that streams in audio and allows you to independently change the pitch and speed through a custom granular engine written in core. Everything is labeled, so feel free to go in and start messing with it all. Also, there is a panel B with more controls for creating Grain Cloud style effects.
The first version of this came from a class I had in 2008 with Martin Zwartjes. Many thanks to him for his amaizng ideas, and general Reaktor wizardry. This version improves the bounds wraping on the streaming audio, adds Hann windowing functions for the grains, applies envelopes to allow for triggering, links the grain width to grain freq, and adds a probability based pitch jitter function. Additionaly, the Spd OffSet knob unlinks the left and right channels.