Anderton
 
Depends on how you define "reasonable."  I don't know much about coding, but I suspect that to add a "simple, straightforward vari-speed function" to Sonar would require ripping the audio engine apart and putting it back together again using a completely different approach. It probably wouldn't be as difficult if all you wanted to do was change pitch and accept that the duration will get longer or shorter (as with tape), but still, I question how many people would consider this such an important feature that they'd be willing to give up all the other cool things that could be done with an equal amount of development work - especially because there are workarounds that so far, have addressed almost all of the vari-speed needs people have brought up.
 
Some of the workarounds, like pitch-up/pitch down voices, aren't even particularly time-consuming - basically, the time required to create a premix. I'd rather spend a few extra minutes on a workaround during the rare times when I need vari-speed than hang up Sonar's development team for several months...maybe Noel could chime in on how easy or difficult this would be. If they could do standard tape vari-speed in a few days, sure, go for it! Otherwise, it's not high on my personal list of priorities.

BlixYZ
if Reaper can implement varispeed, well, nuff said.  
Sonar was the first full DAW to have integrated REX loops, why didn't varispeed closely follow? 

BenMMusTech
After browsing through over3 pages of comments, there seems to be a groundswell of opinion that this feature is now high on the priority list of most Sonar users, Noel!  And I think this is because Sonar is used by composers/producers who are of a certain ilk, so rock, pop composers.  Yes I know Hip Hop, Dance and the like also use Sonar, but it seems to be used a lot more by real musicians. ;)
 

Noel Borthwick [Cakewalk]

BenMMusTech
After browsing through over3 pages of comments, there seems to be a groundswell of opinion that this feature is now high on the priority list of most Sonar users, Noel!  And I think this is because Sonar is used by composers/producers who are of a certain ilk, so rock, pop composers.  Yes I know Hip Hop, Dance and the like also use Sonar, but it seems to be used a lot more by real musicians. ;)
 

 
 
erm I wouldn't draw that conclusion based on this thread alone :) Obviously users who are interested in this feature would respond to a thread about it...

Anderton

BenMMusTech
 
To answer Lynns and a few others question in regards to how good is it in Reaper, the answer is it's flawless.  I can't detect any digital artefacts (noise) in the processed file.

 
I'm still curious whether Reaper's variable speed does or does not change duration with pitch. If it does change duration, and is like tape varispeed, then that's something Sound Forge has been doing for decades by resampling. So apparently it's no huge deal if you're just dealing with audio and not things like virtual instruments. However, I would also think that once the slowdown gets really slow, it would be hard to avoid aliasing or foldover distortion.
 
Also, different people define "flawless" differently. For example, the formant with tape varispeed changes dramatically but there's no distortion or stuttering.
 
If any program can do transposition +/- an octave flawlessly while retaining duration, I want it!!! And I want it even more if it can do this in real time. Meanwhile, IMHO iZotope and zplane have the recipe down best for independent time/pitch stretching.

digimidi
Based on what Craig and Noel said, I'm surmising that Sonar's audio engine is too complicated to implement this feature without a huge overhaul compared to Reaper.  I liken Sonar to Internet Explorer as Reaper would be to Chrome, meaning that Reaper is less encumbered with features while Sonar is much more heavily laden with routines.  I'm not sure if it would be worth it to rewrite the Sonar audio engine just for this lone feature.  Maybe it's cheaper just to purchase Reaper and use it (as some are doing now) along with Sonar, or use another program such as Sound Forge which also has sort of a vari-speed function.  Just a few thoughts...

Counting Coup
FWIW I would pay very good money to have vari-speed on Sonar. It's the thing I most miss having abandoned tape. Afterall, it's what Michael Tretow used to put that zing into those ABBA recordings: double & tripple tracks, each one slightly pitch-varied :-) Brilliant for doing BV's!
(David goes off to stare longingly at his E16)