If cost was no object, I would take the bike out and ride it as slow as I could without falling over. Then I would set the gearing so that at my fall over speed my cadence would be 90 rpm. Since I don't care to go over 30 mph, I would set my top gear so that I would be doing 30 mph at 90 rpm cadence.

Maybe shifting and such would be an issue with this setup but as far as doing what I wanted gearing wise this should take care of me. Just something to think about.