My guess is that it’s too hard (in software) to transform a waveform “on the fly” to a faster/slower tempo without affecting the pitch (and vice-versa).
Dedicated hardware consoles (e.g. Numark CDN88) can do this, and it’s tremendously useful. I wonder how long it will be before general purpose CPUs will be powerful enough to adjust tempo and pitch independently.
Still, I’d add it to the Feature Request List. 
Cheers! Keep up the good work,
–
:- Dabe
Hi OneTrueDabe,
No, it’s absolutly possible - since years! Hardware consoles integrates time strechting (pitch lock) since a short time…
The time stretching / pitch lock feature is on our to-do list for future releases…
Best regards,
Tobi
Make that one a top priority. It is really crucial for some of us. 
I’ll second this request. I’m looking to use some software to replace a set of cd player (pro-deck) for a non-profit dancing group and they adjust the tempo at times for the dancers.
This software is the best I’ve found yet, but this feature is a must!
Feature is available since the official release - UM 2.0.9