Varispeed using CAL: Is it possible?

I'm thinking of writing a CAL script that using X2's features to allow me to do varispeed (my only big gripe with Sonar). Basically it'd allow you to input how much you want to speed up or slow down the project and then it'll change the tempo correspondingly (meaning MIDI stays sync'd) and processes the audio with Groove Clips and, maybe, AudioSnap.

The thing is, I'm not really sure CAL can handle GrooveClips and can't really find much information about it in the help. It all seems to be based around MIDI stiff. 

So, am I barking up the wrong tree with this? Is CAL inadequate for this task? I might look into using Processing and see if that's possible since I remember a colleague using it to control another program.

Cheers.

That's why I need a script. I'm not looking for the tape-stop kind of effect.

I was thinking of using the GrooveClip pitch control to do the pitch. I'm basically trying to write something that approximates Reaper's "playback rate" slider, though this would only do discrete input values, no automation obviously.
The reason I was hoping to write a script was so that it could change: the project tempo(s), turn all clips to GrooveClips with 'stretch to tempo' to do the time-stretching and then GrooveClip's 'pitch' and/or 'fine pitch' parameters to mimic the change in "tape speed". The pitch would be calculate from the amount you wanted to increase or decrease the tempo.

I'm not sure it'd be possible with CAL and I've just seen that it was actually deprecated!

I think I'll have to look into Python but I've got a sinking feeling...

Thanks. Now that I've had more time to look at CAL I can see that. 

I'm now on the hunt for other avenues!