In August 2005 a 777 also Malaysian Airways, encountered an upset caused by the autopilot pitching the aircraft to FL 410 before the aircraft stalled.
Investigation: 200503722 - In-flight upset; Boeing 777-200, 9M-MRG, 240 km NW Perth, WA
Recently there was a warning about cracks in 777 fuselages.
I put it to you that perhaps a similar incident occurred here with MH370 withe the autopilot causing it to pitch to FL450 or higher with the aircraft structure actually failing explosively a la Aloha Airlines, incapacitating the crew but leaving the aircraft in a flyable state. Further Partial destruction, for example of the comms systems, could happen over time as loose pieces of the fuselage ripped away. The damaged aircraft sans crew somehow resumes level flight after the upset, (stranger things have been know to happen to ghost aircraft),but pointing in the wrong direction. It flies off and continues to do so.
After this 2005 incident it was discovered that sudden accelerations during the incident had damaged an accelerometer in the ADIRU and that an other accelerometer had failed previously.
Could it be that MH370, with the flight crew incapacitated, the passengers dying, flew an erratic track because the ADIRU was damaged and intermittently commanded turns which ultimately resulted in this aircraft flying south until it crashed in the sea due to fuel exhaustion?