On Mon, 7 Jan 2008 12:34:37 -0800 (PST), wrote:

[snip]

I also did try turning off the main
feed, which did kill the lights (how could it not, right?), but did
not try leaving the main feed on and turning off all breakers
(although I suspect that must have the same effect, since the lights
couldn't be tied to the main feed since it's 240V, right?).

They could, and yes.

Think about it. 120V loads are ALREADY connected to the main feed (a
breaker is not a transformer). Any other 120V load could be connected
the same way, although this is not desirable.

One more
question - since the lights are all downstream of a single switch,
which works, I should be able to kill the main power, disconnect that
switch from the circuit and be good to go, right? No power to switch,
no power to lights? That way anything else on that circuit upstream
of the switch would continue to function appropriately and even if
there was a double-circuit connection upstream of the switch, I would
be absolved from having to hunt it down. Sound acceptable or am I
missing someting?

Since it's already wired incorrectly, you can't be sure it's actually
hot that's being switched.