Jim,
It's a nice idea and surely needs development. Other than the cutoff dates, the differences I see between the two organizations is that SPA contests are more focused on the competition part where VR/CS events are more inclined on fun competition (so what if your three inside loops look a little like eggs ).
One thing the SPA does not do that VR/CS does is have Class I (rudder, motor), Class II (rudder, elevator, motor) and Class III (rudder, elevator, motor, ailerons). It would also be possible for a guy to fly the required maneuvers with a reed radio if so inclined. A number of flyers are using the old reed transmitters with modern electronics and flight packs.

Here are the VR/CS guidelines for pattern airplanes up to 1/1/70.

Planes must have been designed for radio control.
Aircraft must be built to the plan form of the plans.
Original airfoils must be maintained.
Changes to bolt on wings instead of rubber bands are OK.
Stab location can be altered.
Foam wings can be substituted for built up balsa.
Strip ailerons may be substituted for “barn door” style ailerons.
No scaling is allowed.
The pilot does not have to be the builder of the model.
Original plan materials or construction techniques need not be followed.
Power
a. Any side exhaust two cycle up to and including .61 cubic inches (10cc) is legal.
b. Four-cycle engines up to and including .91 cubic inches (15cc) without air chambers or supercharging of any kind are legal.
c. The use of vintage engines is permitted provided the above guidelines are met, but all engines must use a proper muffler. Tuned pipes are prohibited.
d. Electric power may be substituted for glow; there are no limitations on battery/motor combinations.

I'm in the planning stages for a VR/CS event to be held around October of next year in the NJ, NY, PA, DE, MD region and it would be nice to have VR/CS and SPA join forces. The event will be open to all, VR/CS membership will not be required.

I'd love to talk more about this.