After looking over the many posibilities I have been considering a smaller option. It would be easieer to get started
on a smaller model and learn a few things before going bigger and my boys are 3 1/2 and 5 1/2 would likely fit for a few years.
The following drawings give a basic idea of where my mind has drifted.
The basic goal is to create a smaller model that could still sleep younger children.
Then when we out grow this one sell it and build the larger model.
It would probably be 5' + wide I believe that my wife and I can manage on a full sized mattress.
I would like the kids cots or cushions to be able to fold out of the way.
And as the 2nd picture illustrates it would be fun to have a quick release mechanism to reconfigure them into a bench.
I listed the basic dimensions and would welcome any input as to what may or may not be workable from others experience.
Thanks, Robert

"Experience is a wonderful thing. It enables you to recognize a mistake when you make it again."