Variable Caps

[jmcmahon at prometric.com]

I'm having trouble finding some parts, maybe one of you can help me.  I am
looking for variable capacitors. Not just any variable capacitor, but ones
that can be turned like a pot.  Ones large enough to attach a knob to and
allow realtime control of it.  I have found an abundance of surface/pc
mount and medium sized ones, but nothing to really fit my current project.
Right now, I'm not concerned about which values of caps, but just where I
can find them.  By the way, I am in the US, so a distributor/manufacturer
in the US would be a plus.  Thanks guys, I know you'll come through for me.

       Jason McMahon
  experimental musician
i break things on purpose