Yeah, The Works has some great photos, Meep! I like the one of Richard and Jim with Statler and Waldorf.
Actually, now that I think about it, I used to own that Sesame Street Unpaved book. Richard's name was all over the place, so that's the first time I ever saw his name connected with the Muppets. There wasn't an individual bio or photo for him, only for the people working on the show at the time (except Jim and Frank cause, yeah, they're Jim and Frank!).
But I know Kevin Clash explained why Richard didn't want Elmo. Something like, "Richard's characters were very loud and direct, very specific. The quiet monster didn't work well with Richard's repertoire." So that was my first impression of him, which turned out to be pretty accurate! lol