chucky, I'm really interested to hear what customizations BF couldn't or wouldn't do for you. I think it would be a service to prospective BF customers to know what the limits are.
As for "killers"... the reason why Brompton hasn't made a Dahon killer has more to do with price point than with anything else. Most folding bike shoppers aren't willing to spend more than $500 on a bike (honestly that number is probably $300). Dahon makes several models in this range. Brompton does not. Brompton does, however, make one of the smallest folding bikes on the market. Dahon does not.
All I know is... it's Dec 31st, and I'm about to head out for a party. Happy New Year everyone!