Re: A step-thru china girl. Almost.
You know, somewhere here is a picture of a motorized girl's step-through bike that was very well done. If I recall the builder had rack mounted the fuel tank and the engine was mounted on the secondary down tube. It still offered the advantages of the step-through design even with the engine taking up some of the open area. If I find it I'll post a link here. It might offer some ideas.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"