I got an alternative for you...
Dare makes a b-17 kit. (link below) 75" wingspan.
The kit is designed to be an RC flyable plane. You could build this into a flying plane, then if you feel you must have a larger version, scale it up to the size you desire. The smaller the multiplication factor, the lesser scale error. Example.. 10" span to 100" span, 10x multiplication. 50" span to 100" span, 2x multiplication.
http://www.darehobby.com/airplanes/a...lectric-02.htm
Just a thought.