mxslick,
1: The impedance of the neutrals at feeders and panel buss are (electrically) significantly lower than the #12 or #10 branch circuit wiring thus allowing any noise or harmonics to be "absorbed" (Not exactly the right word I'm wanting, but you get the idea);
Actually I don't get the idea. Harmonics are not absorbed by any conductor or the system.
2: ANY electronic load of ANY kind is far more sensitive to power quality issues than incandescant lighting or pure resistive loads like heating devices;
That is a design problem of the equipment, not a problem caused by the multiwire branch circuit.
3: Electronic dimming controls of any make or style are VERY noisy (just take a portable AM radio near any of those things and you'll see what I mean.);
And how does the use of multiple neutrals help a RF problem where the noise is transmitted through the air?
4: Most of these systems are extremely expensive and sophisticated in their control schemes and do not take kindly to noise issues on incoming power (not to mention the risks of a lifted neutral frying everything)
Again, other than the open neutral issue, that is an equipment design problem, not a neutral problem. Most of the power quality problems that effect this type of equipment are generated by this type of equipment. Why should the electrical system be changed to try to prevent problems that are caused by poor equipment design?
Do you have any technical documentation that shows problems for "sensitive" electronic equipment are caused by multiwire branch circuits?
Don
[This message has been edited by resqcapt19 (edited 06-07-2006).]