It is perfectly possible. Let's face it, no-one knows for sure what Bin Laden looks like, much less where he is. You have to ponder the media mileage and national justification in faking a tape like this, but doing so would be simplicity itself. Remember when Guns 'n' Roses started? They put out a live concert tape of one of their performances, shwoing a capacity baseball stadium crowd going ape at their performance. Except it was Aerosmith's audience, the Gunners were the support band, but it looked for all the world as if they'd conquered the stadium circuit in one go. Less sinister, but equally simple. When you consider a nation who can cover up the assasination of its President, a bit of muddy video of several various bearded gentlemen should be a piece of cake!