So they were smart enough to be tampering with the radar and avoid detection. Plane may be in Kyrgyzstan.
Do you really think that Australia, China, US, Malaysia, etc. would have spent Millions of dollars and man hours searching the Southern Indian Ocean for 2 months if they thought the plane went north to Asia?
I love a good conspiracy too, but the real evidence points to a crash at sea because of the actions of one of the pilots or an electrical failure onboard.
You can never trust eye witnesses.