It doesn't sound like a throwout bearing to me. A throwout bearing usually only makes noise when the clutch is completely out and the noise goes away as soon as the clutch pedal is touched. This is because the bearing has a load put on it by the release fork and stops making noise.

I would put my money on an out of whack diaphragm spring or something having to do with the pressure plate. Does it affect your shifting or clutch engagement, or is it just a noise?

For an ACT clutch, my best price I found for the HDSS and 8.8 lb prolite flywheel was $604 on ebay. ACT doesn't make clutches in stages; but instead, you can mix and match disk types and pressure plate types.