I have read that "the Sheikh has never been safer" was a comment in a captured Al Qaeda document. Here is my interpretation of that remark:

Osama Bin Laden IS NOT in Afganistan or Pakistan. Neither would be considered "safe".

Osama Bin Laden IS in Saudi Arabia, staying at the country retreat of one of his supporters. The mansion is staffed by his loyal followers, and his host comes out every so often to justify having a country retreat. Here Osama Bin Laden is free to operate without restriction or fear.

In addition, since Mecca has the Worlds largest and busiest airport, it is a perfect hub from which to dispatch his operatives all over the world and receive them back on brief notice.

If I were looking for Osama Bin Laden, I would concentrate on mansions owned by his Saudi supporters. I admit that it is a guess, but it is not a stupid guess.