From the article:
"We felt that if we mixed this with another model, we would lose what is so special about us and what we are so proud of," Mr. Peterffy said.
Agreed. To me, it seems like the makers of laser surgery for eye correction, were bidding on an eye glass company. Granted, there may be a lot of money in eye glasses, but the future is laser surgery. Convincing all those eye glass customers to get laser surgery would have been quite a task.
I would be curious to see IB's planned approach to handle the "Pit traded" contracts like REFCO (if they would have won the bid). If this was innovative, then this could have an interesting story.