Thought about this too. Conceivably, you could make it within the specs of a thrown weapon. No core, all foam and coating. And I think it might also be useable for waylay. But I think... not 100% sure...to make it a hand- combatable weapon, you'd have to have it on a stick with a core... Oddly I do imagine something like an ax. BOOK AX.
Your mileage may vary.