Just considering whether I wanted to pop for another plugin - namely, The Waves Abbey Road ADT plug.
 
Why not just build a plug in chain to do what the basic premiss is.
 
I'm thinking:
 
DAW track send>Aux bus
Aux Bus>Tape simulation plug  (to get the tape sound of the printed track)
Tape Plug>Neve Channel Pre simulator (to get more old school warmth and get it into a simulated console
Neve Pre>Tape simulation plug (to get the tape sound of the second tape recorder)
Tape Simulator>Delay plugin with output set to full wet - one slap.  (Might want to put another preamp simulator before or after for more vintage dirt.  On the aux track you would place automation envelopes to vary the delay time ever so slightly and cause the ADT to vary timing.  If the Delay plugin had the old effect of pitch change when the delay time was varied, all the better, otherwise add a pitch change plug and automate the pitch change amount.
Delay Plug in>Neve Channel Pre simulator.
Tweak volume on the bus to taste.
 
Anyone got any improvements on this idea.  I think I'll try this out this evening.

I don't have any ideas for you, but you've just given me a great idea for a Timeless2 preset. Thanks.

I had a play with the waves plug and for 99 bucks, I thought it was great.  Although I didn't purchase, as my 99 bucks went to Sonar 3.  ****ing around with plug in chains just seems like a hassle and u wont get an authentic sound, when I had a fiddle with that plug I instantly dialled up a classic Beatle sound.
 
A work around is to export your file out and import it into Reaper and use their Vari speed function and just create two files with slightly different speeds.
 
It would be nice if Sonar fixed what seems to be a very simple problem and just gave us a Vari speed option may via their new tape emulator.  I mean if a crap program (I don't like the GUI) like Reaper can implement it so well, why can't Sonar??
 
Ben

I gave it a try and it doesn't sound like double tracking.  But then, neither did the Abbey Rd. ADT.  It's interesting and usable once you get it tweaked even if it's just to get people wondering what exactly is going on with the vocals.
 
My chain was Vocal Send>Aux bus>Slate VTM>Waves Scheps 73 (roll off highs and lows)>Waves Super Tap 2>Waves H-Delay>Slate VTM>Waves Scheps 73>Main output.
 
I used an extra delay in the chain at a fixed delay time (15ms).  I tweaked the wet/dry mix of that before it hit the H-Delay which had it's delay time automated with random envelope changes from 5ms to 25ms.  I used the Scheps 73 because the combination of the H-Delay and the Virtual Tape machines put a lot of extra hiss in the chain and I had to get that under control.  It was a 30 minute play time experience.  
 
I ended up using it for a bit of lift on a couple of solo sections for a lead guitar and for the vocals for a track. 

I saw an 'Into the Lair' with Dave Pensado do the automated delay and pitch thing on a cloned vocal track, but no tape warmth. I never tried it, but since you've reminded me, I'll have to try it out. It sounds like a great idea on lead guitar as well as vocals. Can you automatically generate a random envelope in Sonar X3? I think this is why I didn't try it; too tedious making the random envelope.

Can you automatically generate a random envelope in Sonar X3? I think this is why I didn't try it; too tedious making the random envelope.

 
Random Pattern Tool.  One of those useful features that you never seem to hear much about.

Jimbo21
I saw an 'Into the Lair' with Dave Pensado do the automated delay and pitch thing on a cloned vocal track, but no tape warmth. I never tried it, but since you've reminded me, I'll have to try it out. It sounds like a great idea on lead guitar as well as vocals. Can you automatically generate a random envelope in Sonar X3? I think this is why I didn't try it; too tedious making the random envelope.

It doesn't look like the Random Pattern Tool that b rock mentions is something that is drawn automatically.   I wonder if there might be a CAL program that does that?  It's been so long since I used a CAL program that I'm not even sure SONAR X3 includes it.
 
In my experiment, I was using Pro Tools 11.  It was a matter of holding down the Windows Key + Alt and clicking random spots on the automation lane that I set up for the Delay time.  That created a node and it didn't take very long to do the job.  There was a little value window that kept me updated as to the delay time.

it's way more fun, and sounds better, to just actually do double tracks.
 
 
IMHO 

This is correct, in SONAR the random pattern would have to be drawn by hand but should not be a problem just drag the tool in the automation lane. CAL, while still included with X3, does not do audio automation.

Melodyne has a video tutorial on using, um, melodyne to simulate double tracking. Their claim: it's the perfect tool for doubling vocal tracks. (Hey, saw it on the inet, must be true!) You can also do the harmonies thing with it as well. I've done the harmonies--works nicely. Haven't tried double-tracking yet. Seems you could also mess with the formants a bit as well as just pitch, might add a little more bang for your buck? 
 
http://www.celemony.com/y/08fx6x
 
If you have melodyne.