Thanks to Bill Hannan and David Aronstein for discovering the work of Gordon Pollock, who sold a cool walkalong glider called the WonderWing in the 1980s. Gordon told me that he made the gliders from indoor balsa wood and condenser paper, both of which are very lightweight. As you can see from the illustration below, the front weight of the glider also acted as a canard. I've tried that on the foam gliders and it greatly inproves the pitch stability. The canard in front of the wing is set at more of a slant (higher angle of attack). So the canard stalls before the wing. With less lift from the canard, the wing pitches down before stalling. It's really fun to see the theory actually work in practice.
Gordon said he might have a couple of old Wonder Wings stashed away. I'm hoping he'll be able to send some pictures to add here.