There are lots ways to do process a clone of your original track. The more clones, the merrier. You can also try cloning the processed tracks to take the processing further.
1. Check out the article about ADT (automatic double-tracking) using Melodyne Essential I just posted in the Cakewalk blog.
2. I did a lengthy series of posts about how to do varispeed effects with Sonar's Loop Construction window but
NOT using it to create Groove Clips. You can use varispeed to change the formant by speeding up or slowing down, then do ctrl-click+drag on the clip edge to restore the clip to the desired length. (BTW ignore the guy saying it doesn't work, he apparently thought the technique involved making Groove Clips.)
3. If you still have V-Vocal installed, change the voice formant and timings somewhat.
4. Combine all of the above.