There was one other person besides Bob (and later Peter) who was privy to Rhoda's true identity. That would be Dr. Carl Miller, played by Henry Beckman, perhaps best known as the salty Captain Clancey on Here Come The Brides. Miller was the actual catalyst, having created the robot, but was only seen in two other episodes besides the pilot. Bob told everyone that Rhoda was Carl's niece, which accounts for the last name. I personally wish Beckman had put in more appearances because he seemed like an interesting character. I mean, anyone who can create such a gorgeous robot...In the pilot, he's called away to Pakistan, leaving the robot in Bob's care and creating all kinds of pandemonium for the psychiatrist. A side note--the parallel with I Dream Of Jeannie is very interesting. IMHO, Bill Daily as Roger was a rather cheap carbon copy of Jack Mullaney's interesting portrayal as Peter Robinson.
-Roy
-Roy