There was a Grand Slam on ebay. Auction finished today. Had a starting price of $1000 and got no bids.
I played a Grand Slam machine one Friday night back in 1976 at Macquarie Uni and loved it as I could get the home runs for a free game, plus the roto target was a novelty for me. Don't know if it is a game that holds interest, but it is a GTB and is a wedgehead.

Did you end up buying the one you were after? If so, how much?