So, Crusader, what you're saying is, that if you play a note on the 12th fret with "open string to the nut" behind it, it would sound differently than if you played the same note but capo'd?
Move the capo around (behind your fretted note), and the sound changes?
Interesting...
I still don't understand how you would capture a specific node, if the "node" moves around as you fret...
Not just that, a pickup doesn't just capture the vibration directly above it. The field is much too wide to try to zero on a single, specific point.
But hey, what ever keeps you occupied...