BenMMusTech
Here is the track I did, everything was done in Sonar apart from the tape speed effect.  You might be able to hear stuff that I can't.  The tape speed is in the break down after the middle, and the track speeds up in the solo.

Given the program material, I really can't tell what's going on with the varispeed fidelity. I'd need to hear it on an acoustic instrument or something like a relatively sparse pop song.

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)

my vote for vari speed + 1000 been waiting a few versions now for it.
 

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)

I had a breakthrough in the studio tonight regarding varispeed and Sonar. I'm presenting the first solution here, which is about doing true tape varispeed on individual clips. I also have a solution for doing what you describe with doing slightly pitch-varied tracks but I'm still finalizing the writeup.

Craig. Thanks for this. I look forward to trying this when I get to work in the morning.
However to be any real use in the longer term, it needs to be a simple knob that takes your entire DAW up or down +- x%: just like with tape. I almost jumped ship once for lack of it and I've been a loyal chapie since DOS4.5

 
It is also a workaround to varispeed the complete Sonar DAW by using hardware which provides sample rate offset.
As I could not find all the info I searched for I want to share the results of my tests:
http://forum.cakewalk.com...-m3102282.aspx#3102282

vari speed has been coming into my thoughts as well with sonar, interesting Ben should bring it up

Just a bump on this. Bobben has come up with an interesting idea here for the vari-speed Sonar dilemma.

I am wondering what others with more technical abilities think of his "technique"

Follow his link above to see what I am talking about.

I have now had success in Sonar X3 with +/-12.5% hardware based varispeed at 88.2kHz by using Sony CDP-D500 CD player as master clock for my RME audio interface:
http://forum.cakewalk.com/FindPost/3102812

Before I went 64 bit with Sonar I used a small DX plugin called PitchWorks that worked really well in real time.  You could change pitch, and/or tempo separately or together.  I could place it on the Master buss and affect all audio or use it on individual tracks.  As small as the plugin was (628kb) I can't imagine there is really that much to implementing varispeed.  Heck I think it would almost be better to have it as a plugin personally.
 
Dan