Most Pitch Shifters can do such an effect. I dont think alot of Pitch Transposers can do more than a gliding slow down, but you might try one.
I think I've read that your using SX. Do you have a dedicated Wave Editor. CEP has a plugin called Pitch Bender which has a preset for your desired effect. I'm sure most other Wave Editors include something like it.
Try the demo, or email a buddy with CEP and have them effect the track for you. Hey, I'll even do it.
Good Luck,
Chris