Thanks, Mr Wizard!
I will have two battery banks. I already have one of those giant blue sea switches to switch between (actually, I have two, in case I need).
But the problem is that I will have so many things wanting to connect to ONE side of the switch -- charger, alternator, inverter, small DC loads. I could put a bus bar, but I would still want a way to shut things off individually.
Can I use a small breaker panel designed for AC? What size AC-spec breakers would I want for 100 amp DC loads? Is 15 or 20ish right?
Am I reinventing the wheel here? Isn't there something RVs normally have?