Well after cutting out a cardboard profile I realized that I really could get by with 4 foot sides rather than 5. To me the 5 foot sides were just too high for the look I wanted. And I was dreading having to scarf or lap those joints together. My test piece worked great though. It's 10 feet long, so I had to lap joint 2 feet onto the end. The joint is going to be re-enforced by the cabin wall, so I think I'll be okay for strength... and to cover up the bad lap joint I did on one of the sides.
Here is a pic of the cardboard profile. I am glad I took the time to do this and to be able to visual it in 3D and life-size. I knew I just had to have that tablesaw for its box
And so on I went to drawing the profile out on the plywood. I was very nervous about this because I painted the outside and varnished the inside beforehand and I didn't want to screw up!! Well all went well though. Many many thanks to Andrew for his awesome designing. I used the Gruman 2 profile design in his library.

He was so kind to even draw a 5 foot high version, but I went with the 4 foot verson after all.
Here is a couple pix of the sides view. Hubby and son are holding the sides up for the picture. Boy oh boy those sides weigh alot!! Everytime I want to move them I have to ask for help. IF I do another build I definitely will be framing the sides.
Next I've got to cut the doors out.