Well I guess the first thing to drop would be the 10 cc limit...
Lets say for a starting point we set 1.6 cu inches as a max displacement, or any combination of engines for that max. So we can look at building an airplane rather than an overpropped glider.
Lets try to set a few parameters, wing loading should be up to the builder, but for a max model weight lets say half of the AMA legal limit or 27.5 lbs dry, on a 8 foot max span wing. How does that sound?

Lets try to come up with something that can push the limits of R/C speed but be within the reach of the average hobby budget. If you have a better idea of what design should be used as a starting point then by all means join in. Keeping in mind this goes more toward an unlimited class than an FAI type of aircraft.