It never hurts to ask if Phoenix will build one up for you. I am sure they have the plans. You would have a better chance if Kermit was still chief, but just maybe the new guys will see this as an opportunity. Extend the original plan the extra foot to current length and offer twin and walk-around rear queen bed options. A walk-around rear queen bed without the need for a slide out used to be very popular, desirable and also done to address the weight limitation of the times. There was much less weight hanging behind the rear axle, eliminating even today's concern of over-loading the rear tires. Phoenix is desperate over this matter as reflected in them deleting the spare tire.