John,

You wrote: "I have not seen nor heard of anyone installing a second pitot tube"

I have an LNC2 with two heated pitot tubes.  I did this because I upgraded the panel to have Dynon Skyview avionics with their heated AOA/pitot tube.  The Dynon tube requires mounting with the tip more than 6" behind the wing leading edge and is much longer than the AN-5812 pitot.  This meant that I could not just pull out the original tube and put in the new.  The new one is mounted on a glass mast built into the aileron bell crank access cover.

Didn't remove the old because...well, just because.  Everything works fine and they read the same.  Airspeed sensing uses a common static source.

Tom Thibault
LNC2