Keith,
You have a fex excellent points.
However, my personal knowledge of internal aerodynamics is limited, so all I can do is quote existing litterature, which all agrees on supersonic intakes producing a significant part of the thrust, be it SR-71, Concorde, or military jets.
Brian,
You found a rather interesting quote:
"Ben Rich.... refers to the compressor as "a pump to keep the inlets alive"
It should answer awblain's query:
"If the section of wing incorporating the inlet was broken clear from a Concorde cruising at M2, all the way back to the compressor face, would the released inlet really accelerate forward due to this inlet thrust...."
The answer is 'yes' , on condition that you have some way to continue "sucking" out the same amount of air from the back (at the compressor face location) to maintain the flow conditions inside the inlet itself.
Brian,
Your initial quote in italics does really only apply to the SR-71.
On Concorde virtually all the air from the intakes goes through the engine, and only a small amount is bled around the engine to cool the engine accessories.
Also, Concorde does not use reheat (afterburners) in cruise at Mach 2, only during supersonic acceleration to "get over the hump".
CJ