The first widescreen LD was probably Woody Allen's "Manhattan". He had the clout to demand it be letterboxed from it's first video release in 1984. This included VHS, Beta, and tv broadcasts of the film! (All these early video versions have gray instead of black bars.) I don't think a pan and scan version even exists.
Believe it or not, the honor of the first ever widescreen video release of a movie actually goes to CED!