Regarding the four one-bids format:
If you won a car, and consequently, were the top winner, why on earth would you choose to play in the Showcase Showdown? Is a 1/400 shot at $11,000 worth it to possibly not even qualify for the boatloads, or carloads of prizes?
I would give the top winner a bonus spin for $5,000 or $10,000; after the other three players battle for the other spot.
Here's an idea I've tinkered with after seeing the original TPIR:
Have the same four players for the entire show. Bring out one-bid items, the winner gets that, and the chance to play a stage game. Top two winners would move up to the Showcase. I had an option if the show went to returning champs as a nighttime show, but it's not appropriate here.
This format means that while only four people get called to play, they all have relatively the same chances to win, as opposed to the person who is the ninth name on Randy's list, and has to bid first on the one-bid.
Travis