The fact is it would be a very
large stretch from the FARs to say a CFII
can log dual while sitting in
the back of the plane.

Why? While unusual, I don't see the problem at all. The instructor is
not required for the flight to be safe. The pilot in command is seated
at a control seat. Instruction can very effectively take place from the
back seat.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.