Ritardandi and accelerandi when live-looping.... any ideas?

[Per Boysen <perboysen@gmail.com>]

A long standing frustration of mine is that I'm finding it so  
difficult to do ritardandi and accelerandi when live-looping. Has  
anyone else been thinking along the same lines? Maybe someone has  
ideas on how to get away with it?

I was listening to pianist Rob Costlow and experiencing how powerful  
instant tempo changing really is.
http://magnatune.com/artists/albums/costlow-woods/

One technique I use today is to loop a phrase and change the playback  
rate so it will play in a different pitch and by a different loop  
length. If you combine that with other simultaneously sounding  
phrases that stay on the beat you get close to the feel of rit 'n  
acc. But it's not the same thing. Maybe if using a Repeater (that  
does instant time-stretching to keep pitch the same over tempo  
changes) and "play" a continuous tempo controller along with  
instrument and loopers? Any ideas on that?

Greetings from Sweden

Per Boysen
www.boysen.se (Swedish)
www.looproom.com (international)