HazelNuts39:
The more I think about the proportion of energy dissipation provided by altitude vs. air speed, with a relationsship of 4:1 for altitude, the more a high altitude stall seems probable to me.
If we stall it first, we would have to have only ~ 0,8m/s^2 to decelerate horizontally to 50kts.
The remaining energy would be dissipated by the vertical drag while falling belly first.
Vertical drag should be massive. Assuming a Cw ~1 in the Vertical plane (which should roughly fit), an A330 would arrive at a terminal velocity of ~150kts.
That combined with a forward 50 - 100 kts wouldn't be too far off the attitude which BEA concluded for the impact.