Bill wrote:
....

Is there a rule that says a subpanel has to be a very short distance from
the main panel? I would position it about 10 feet away if I could.

That's cool...

Is anything (code) likely to prevent me from doing what I want with 15A and
20A 120v and 240v circuits from a subpanel (like having 10 of them)? As you
mentioned earlier, I'm likely to stay far below the 50A threshold
in terms of actual usage.

No, that's what subpanels are for -- just size it for the number of
circuits of the type you want/need and make it's service breaker the
same or smaller than the feed. If it's close enough, you can (I think)
get by w/o the local breaker/disconnect but it's certainly more
convenient and I'd likely not scrimp...

Good luck, it ain't rocket science; most of the Code is simply
formalizing what is common sense; it just takes somebody to point out
what that commonsense is for the first time and NEC is the standard.
The self-help books are pretty good in general at separating the code
legalese and turning that into what actually needs doing...

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