I though I only had 3 or 4 good channels (I have 5!), so I recently received quotes for CEM chips from icelect.com. I only found them through searches via Google... so I can't vouch for their quality, etc. The '72 price looks reasonable, though.
Part:CEM3374
Qty: 6 Min - Price: $ 72.00 each
Mfg: CEM - Description: ELECTRONIC COMPONENT : DUAL VOLTAGE CONTROLLED OSCILLATOR. 18 PINS : DIP-18 PACKAGE
Qty: 6 Min - Price: $ 72.00 each
Mfg: CEM - Description: ELECTRONIC COMPONENT : DUAL VOLTAGE CONTROLLED OSCILLATOR. 18 PINS : DIP-18 PACKAGE
Part:CEM3372
Qty: 10 Min - Price: $ 15.00 each
Mfg: CURTIS - Description: ELECTRONIC COMPONENT : SIGNAL PROCESSOR : 18 PINS : DIP-18 PACKAVE
Qty: 10 Min - Price: $ 15.00 each
Mfg: CURTIS - Description: ELECTRONIC COMPONENT : SIGNAL PROCESSOR : 18 PINS : DIP-18 PACKAVE