Is this possible?
Would it help the issue if I shrink-wrapped the exposed shrouds in some sort of insulation (electrical tape, maybe)
Is it possible that there connection to the sled is not right and I need to do some tinkering?
When it comes to noise I'd be hesitant to declare anything impossible...
Anything unused should be covered... Try electrical tape or shrink tubing. For the RCAs you could also try muting plugs (get the mating sockets and solder wire from center to shield, so that the center pin is attached to ground)
If it got worse when rewired I'd suspect either something not properly connected, maybe at the sled connector, or that you have a severe noise generator somewhere and that you got the wiring closer to it now...
Inspect the RCA wires as they connect to the sled connector - also check the connections to the connector on the inside of the empeg.
Have you worked through the noise problem solving flowcharts Tony links to in the FAQ?
Are you using the stock harness for ground? What happens if you temporarily attach a [16 gauge or thicker] wire between the empeg chassis and a good ground point?
/Michael