MLS-12D and others,
The reason for the white colour is not so much for UV protection, but because coloued gel-coat gets very very hot in direct sunlight. This could breakdown the internal structure of the FRP components (wings, fus, etc). The big problem is that this damage is not visible until it is too late.
Newer GA and commercial aircraft that make extensive use of FRP will also be all white for exactly this reason.
Some gliders have had the wing tips, nose and part of the rudder painted in bright colours - in areas outside those considered critical or high load. In practice, they make absolutely no difference to visibility.
I would be interested to see someone research using the reflective tape used in marine foul weather clothing. This could be set into the gel-coat and achieve a good finish. As it reflects light, heat build up should not be a problem.
From a different perspective, when flying in airspace designated for see and avoid, flying an aircraft with a limited view could be perceived as the problem.
Increasing the amount of controlled airspace is not the answer. If you reduce the area available uncontrolled, you just increase the density of aircraft, increasing the risk of collision, you also increase the risk of airspace infringements which is bad for everyone.