Seems to me that landing gear door damage (by errant foam fragments) would be a likely culprit. Breach that space with a jet of superheated material during reentry, and the tire rapidly reaches an acutely overpressurized state causing the mother of all blowouts--in the gear well.
Structural damage to the wing, either directly, or as the result of further exposure to reentry temperatures of unshielded structural elements could cause wing failure, loss of attitude control, and breakup of the orbiter.
I'm glad they are looking at all possibilities, but I think we are back to the basics on this one, much like the O rings on Challenger.
There is a short indistinct call from the spacecraft and, almost at the same time, Kling says the landing gear tires have lost pressure.