I have two, both of Wheel Of Fortune; I don't know if there was one done with Chuck Woolery and Susan Stafford - or Pat & Susan for that matter. Wouldn't be surprised, though.
The A-Team did an episode which began with the head guy (forgot his name) appearing on the show and winning big, buying a cigar case among other things; It had Pat, Vanna, and (I think) Jack Clark as themselves.
L.A. Law did one that I've likewise only seen once - the episode was "Vowel Play" and began like a BOB GOEN episode, complete with full open and everything. Shortly after the puzzle was solved it went right into the opening sequence. I recall the Phrase used - BALD IS BEAUTIFUL. Bob, Vanna, and Charlie O'Donnell played themselves.
If somebody could find these on YouTube, that would be great.
-Daniel