I know several people that have bought Bonevilles as their first bike. I think that with some women, they are reluctant to get a bonnie as a first bike, because they feel it is too tall for them.
I think you are right, resurect the Speed Twin name. Use the 790 cc motor, put in a bike that is a couple inches lower than the Bonnie and use a single seat that is similar to the stock seat on the America, and bars like the ones on the Speedmaster.
Soren