Well, as a local "sciolist" here at Pprune, please allow me to offer an observation.
I'm fairly convinced (subject to change by virtue of better facts) that the fire was internal, based purely on photographic evidence. I notice however that the forward fuselage top does not appear to be damaged. One might speculate (as any good "sciolist" would) that if the sparking metal fuselage was scraping the runway surface where the nose landing gear collapsed, then cargo in the forward fuselage areas could be ignited by said sparking. Given the rapid response of fire rescue and the possible spread of the fire from the forward section to most of the cabin, suggests a very hot and fast spreading fire, sufficient to overwhelm the local fire brigade before they could contain it. However the apparent undamaged forward fuselage top would seem to suggest that such a hot and fast spreading fire could not have originated in the forward fuselage area.
Question, where then did the fire originate?
BTW JW411, you're definition of a "sciolist", "One who speaks with fancied wisdom but little knowledge; a smatterer", fits the contributions of many experts here at PPrune, during the early stages of an accident investigation.
