I'll admit to lurking, but I thought you had all of the feedback vis-a-vis 50cc sized Ultimates that you needed.

There are a several engine choices in the 50cc size with DA, ZDZ, BME, and Brison coming to mind. This is a nice and competitive segment of the engine market that should make many good engine choices, at reasonable prices, available. Stick to nothing bigger than an Ultimate that will have wild 3D capability on one of the strong 50cc engines.

Also, make the stabs removeable for easy storage and transport. That may mean no external tail bracing... Also, ensure that it can be transported in a normal sized SUV, e.g. Ford Explorer, Dodge Durango, etc. I think that would make the max fuselage length 82-84 inches with the spinner. A removeable rudder would help keep the transport and storgate length down too...

As already mentioned one servo per aileron and airfoil shaped stabs and rudder would be nice.

I don't care much if it's made from foam or a built up structure. I just want it to be light and strong. I want models that are built to fly -- not to survive crashes. When I want something durable I'll throw together a SPAD...

I guess that's about it for now....