i really not sure how much the highest win/profit in bitcoin gambling history because i am not following the winner prizes. maybe its more than 1 bitcoin because if we make a bet in 1 bitcoin and more, then i think the amount that we can win is more than the amount we bet but i don't know for the truth, i only make a small win.
I saw the max profit in a single bet is 29btc in bustabit site , where one of the bigh players who play the highest limit bet and hit the bumper by hitting the max earning per bet burst and that was 29btc and he hit it and that game was stopped on his winning before burst.