It's just granular stretching isn't it? Albeit very very well done granular. In theory it's perfectly possible to do it in max/msp, but I'm not sure how to make it sound that smooth. All my attempts result in really nice smooth textures, but either AM sideband artifacts, or audible random position movement that has to exist to prevent the AM artifacts. Although, these problems would still exist implementing it in any other programming environment as well, I just need an improved method!

I'm sure someone else more helpful will chip in!

Elasticindex~ is what got me interested in the extreme-stretching thing. But it's not hard to make a patch with native msp objects that sounds just as good.

Csound does a pretty good job of time stretching as well.

I tried Jean-Francois' "Freeze" patch and got some fantastic results---really great, other-worldly sounds. You can probably get a ways by looking through them, it looks like there are also some that deal with stretching rather than freezing. At the very least you'll get a lot of insight into the spectral processing side of things...

http://www.jeanfrancoischarles.com/2008/10/freeze-sound-with-maxmspjitter.html

Try Paul's Extreme Sound Stretch: http://hypermammut.sourceforge.net/paulstretch/

have a look at the grain tools externals. www.LowNorth.nl

it has some examples of granular sampling and stretching...