I think your tuna can idea is right on track but to jazz it up I think I'd head to the thrift shop and look for some kind of little decorative dish to use as the base - I found an ashtray-sized enameled brass bowl for $1 I have set aside to make into a pincushion, as soon as I decide what I want to stuff it with. I think wool is good for the lanolin. Or emery, if you want a "sharpening" cushion. Maybe both?