Looking for large number of older used modulators. Need both cut channel and frequency agile. Must be located within the CONUS.

I think possible suppliers to you will need more information to determine if their old items might be of use to you.  

An agile frequency modulator might comprise simply a synthesised oscillator plus modulator chip.
 
Example synthesised oscillator for freq range 1.7 - 2.2 GHz (100kHz steps):
ANS2-1700-100 1700-2200 from https://www.atlanticmicrowave.co.uk/
https://www.satsig.net/images/synthesised-oscillator.jpgmore details

Example modulator for freq range 1.8 - 2 GHz:
IQBG-2000A from https://www.minicircuits.com/
Surface Mount I&Q Modulator, 50 ohm; LO Drive +10 dBm from $24.95 qty.(1-9) 1.8 to 2.0GHz
https://www.satsig.net/images/iqbg-2000a-surfacemount-modulator.jpgmore details

You need to provide a full technical specification for what you actually want.  Frequency range, step size, physical configuration etc.

Best regards, Eric.