Looking at alternatives to SONAR.  I use it's "fit improvisation" all the time -  map the song to a tapped tempo to create a varying tempo map.
 
Sonar does it
Cubsae does it
Reaper does it
 
What about Mixcraft and Studio One?  I have looked (google, youtube) but cannot find any "easy" way in studio one and nothing on mixcraft.
 
NOT interested in paying for Melodyne Studio $$$$ to do this automatically.
 
 
 

Didn't Studio One introduce the Melodyne Extract Tempo feature before Sonar. This could be used in a similar way

Same issue

Seiting midi clip timebase to seconds, and then performing tempo while playing the clip is as far as I've gotten. There are several videos out there for creating a varying map, but they are not simple.

Yeah - have not found a simple way like REAPER, Cubase, SONAR.  Doesn't seem to be something they care about.
 

DP has some truly excellent facilities for this. You can tap along, or adjust individual barlines and it'll calculate new tempos in configurable ways. You can also calculate multiple possible tempos to hit multiple marked locations. If this is something you do a lot, I would try the demo.
 
It is, of course, pretty different from Sonar. But I am a fan.