What generation of PCM do you have, gen 3 or 4? I was thinking my Gen 4 had something like what you wanted, I know under the program in HP tuners there is an RPM and TPS option to disable the AC. I had hoped to use this on mine but haven't gotten that far into it yet.
If running through the PCM isnt an option I will most likely go with something like what is shown in this manual from Holley.
http://documents.holley.com/199r11334.pdf