Grease was stereo, not mono. The problem with that one is that finding it in digital stereo is extremely hard. The common laserdiscs are analog - LDDB claims there was a stereo repressing, but SilverWook has bought at least one copy that claimed to be the digital reissue, and just got analog.

SilverWook did do a rip of the hi-fi stereo VHS audio, but it's not actually released to anyone yet. And I've notified Buster D about the 90s Japanese LD (pre-20th Anniversary) that does have digital sound, if he ever locates a copy he will do a bit-perfect capture.