Thanks for both links - I don't follow the other old-school-RPG blogs as much as perhaps I should. About 20 years ago, Knights of the Dinner Table comics had an interview with Dave Arneson where he told a story about getting percentile dice in England in the 1960s (mentioned in the Ebay listing above). Jon cast doubt on this story when Playing at the World was being written, but as time goes on, we discover more & more pre-D&D games which used polyhedral dice.