Sideslip angle on landing in a crosswind will also be limited by the angle at which the wingtip or engine pod/prop will hit the ground. In the 744, that's about 8 degrees. For very heavy crosswind, crab is used in conjunction with a slip of 5 deg max, and the airplane can be landed in the crab. Inertia straightens out the airplane on the runway very nicely, as long as you are tracking straight at touchdown.