Tubby,
Geez, I can see what you mean with all the fuel tanks completely full on an empty aircraft. The total weight would be equal to the maximum TOW, actually, slightly more.
From the Airbus CG chart, I calculate the max operating aft CG limit of 39% @ 205 tons and your 37% estimate pretty much coincides with the BEA projection at the time of the incident.
Thanks for your input on the fuel transfer to and from the trim tanks, I was trying to understand how this might work.