Welcome 24v v6
" .. Now that I've probably alientated everyone with my one and only post in support of Tella... "
No, you haven't.
"When I turn the steering wheel,"
Left or right or both directions?
"at a certain point I can feel movement under my left foot on the floorboard - like something is loose right under my foot. The car's drivability seems absolutely normal. Thoughts?"
First the easy one, remove your driver's side carpet and see if it helps. I read once that somebody had the carpet roll up and had problems with the clutch pedal (and not being able to change gears because of that).
Then do you clunking noises when you go over a bump? Then you may want to do the "wheel bearing", etc. tests.
Edit. This thread has some interesting points.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=1074062&Forum=trouble&Words=wheel&Match=Entire%20Phrase&Searchpage=2&Limit=25&Old=6months&Main=1074015&Search=true#Post1074062