Yup. Melodyne would be my first choice. Whether or not it works would depend on the nature of the "warp". Tape stretching can cause "wow", which is a slow pitch change that can span many notes. I don't know if Melodyne can deal with that without a great deal of tweaking of individual notes. But if it's a faster frequency modulation, Melodyne has a nifty vibrato-flattener tool that'll fix that right up. It's not in the lite version of Melodyne that comes with SONAR, though, so you'd have to spring for the full Studio or Editor version ($$).