To Pick a Cable,,,,,,

I don't think you need to run a power cord all of the way to your system. I think that is overkill. You should be able to get by with a well built corcuit breaker running a decent 10 gauge romax, with or without power conditioning. If it makes you feel good, get the power conditioner---it won't hurt.

To answer your second question first. Yes. I have installed a cryo-dipped hubbell IEC at the end of my 20amp dedicated line and plugged it directly into my amp.

It wasn't pretty. It took all of about 5 seconds to recognize the negative sibilance without my passive in-line conditioner in place. Not to mention the other negatives such as raised noise-floor flattened and shrunken soundstage, etc.. Even a good aftermarket power cable will probably offer sonic improvements over the straight service panel to amplifier strategy.

As for your proposed alterations, I would do everything reasonable to keep the components close and the cabling short.

Not to mention that it sounds like you will not have any properly constructed racking system for your components. Therefore, all air-borne vibrations will remain trapped within the components and reek havoc at the micro- and even macro-dynamic levels. (it appears that some people prefer this)

As for your last question, I would guess that one would want the service panel as close to the components as possible. So as long as the service panel was at least 3 or 4 feet away.

-IMO

I would be concerned about meeting electrical code. Unless you run a conduit all the way to your component and connect it to the component, this will probably not meet code. If you have a fire, your fire insurance will likely not cover it.

I would run plastic conduit to an outlet and then a low-inductance cord to the component. Run three twisted 10-gauge THHN wires inside the conduit, not ROMEX.