In my opinion, all this speculation is BS of a spectacular degree. First of all, I cannot imagine a shoe bomb being able to do the damage experienced in AA587 or TW800. AA587 seems like a fairly straightforward materials failure - just look at the images of where the bolts tore through the composite. Explosives damage would have been quite different (how would you blow off the rudder anyway, with a shoe? Throw it out through the ceiling?
And honestly, a shoe bomb detonating fuel tanks in a jumbo? I don't know about his shoe size, but to cause enough damage to blow the way through the floor and outer tank skin, and ignite the fuel as well..... Based on a shoe?!? Not a realistic scenario. Especially as the explosion would take place undirected - i.e. radially. You could not direct the blast into the floor - it would do most damage where it encounters least resistance - in the passenger cabin.
Media panic. Exaggeration. Hysteria. Exactly all of the things I despise about the media - and the uninformed viewers / listeners / readers who soak it all up...
Next thing we'll hear is that Concorde was brought down by a shoe bomb. After all, it has so many things in common: It flew out of Paris, it was scheduled to fly across the Atlantic, there was lots of fire and explosions.... Jeez, why did no one think of that?