tempo grade?!? plug-in or techniques

Hey guys, i want to do a tempo grade on a recorded drum part... essentially i want to process the audio file so that the start is at it's original tempo but it get's faster as it goes along, ending at a much faster tempo. I have tried working with VariFi... tried everything and i can't get this effect out of it. Does anyone else have any ideas as far as a plugin that might help me with this or a technique. Thanks for any and all help p.s. is there any way to get the tempo ruler in PTLE to accelerate over time from one tempo to another? thanks

Graphic mode in Serato Pitch 'n Time. Rail

hey thanks. i'll check it out