high frequency intermittent noise

I would assume he could do what I've done. If there's some point of weakness that might sniff it out. Referring to Atmasphere's post about resistors, the one thing an F5 has is resistors. No caps on the amps at all. Just 8 big filters in the PS. That may explain it's rejection when placed near the amps. I accidentally neglected to put a CL60 on the ground though. That may explain why I get it through the power supply. 

You may be into something with the building system. Some security systems use cell connections to avoid the possibility of wires getting cut or just running more wires period. 

I found a set of RCA shorting plugs. I turned everything off except for one mono block, inserted the RCA shorting plug, and the noise is still present.

I tried a different power cord, and the noise is still present.

I tried an XLR cable between my power amp and preamp, the noise is still present.

I have ferrite beads (made of material 61) on order.

Sweet lord, you poor man.

So.. Those copper mesh curtains.. You could lay one on the floor, stack your equipment on top, then wrap the curtain up and over, creating a true faraday cage, as long as you remember to ground it to a pipe or the ground in your outlet. Test to see if an actual faraday cage works.. If so, you could build a nicer looking one integrated into your rack.

I found a set of RCA shorting plugs. I turned everything off except for one mono block, inserted the RCA shorting plug, and the noise is still present.

Try this.
Do you have a roll of metallic tin foil in the kitchen?

Unplug all the other power cords from the AC power outlet. Reason? To eliminate the chance they will/are acting as receiving antennas and induce the RFI signal into the power cord of the mono amp.

Wrap the tin foil around the speaker cable for the one mono amp being used for the test. Be careful to keep the tin foil back from the amp terminals as well as speaker terminals. An inch or two is fine. (metallic tin foil is conductive). For the test the foil should not need to be grounded.
Plug the mono amp directly into the power wall outlet. Check for the RFI signal noise.

Still there?

Next thing to try.
Wrap tin foil around the power cord for the mono amp. Just the cord not the plug body or the IEC connector. (remember metallic tin foil is conductive). The tin foil will shield the hot, neutral, and equipment ground wire. The tin foil should not need to grounded for the test. The tin foil should reject the RFI noise, if it is radiated through the air, from entering the conductors of the power cord.

Plug the mono amp directly into the power wall outlet. Check for the RFI noise.

If the noise is still present you might try earth grounding the tin foil. Though I think it would not be needed for the test.
You will need a piece of wire. Any size will do. Bare one end of the wire wrap it around the tin foil, at the plug end of the power cord, a couple times or so and then twist the wire to itself to secure it around the tin foil. Bare the other end of the wire, amount stripped depending on the wire gauge of the wire. You may need to fold it over itself a few times to increase its’ effective size. Insert the wire in the "U" shaped equipment ground hole of the wall receptacle.

The power cord is my antenna, I switched to a non-audiophile power cord and was able to move the power cord around, up, down, and around (could never do that with what I am using), and yes, I could affect the noise.

I'm wondering if I'm now in the market for a new power cord?