For those of you with a lathe, mini lathe or a friend with either it's quite simple to purchase a rod of Acetal, nylon or acrylic etc and machine exactly what you require. I myself have champagne corks in (too many) saxes and recently decided to - machine up a few 'nice' end plugs on my mini lathe. Quite a bit of fun too, takes about as long as drinkin' a beer or listening to a CD. Personally I chose Acetal (aka delrin). For those with a wood lathe OR friends with a wood lathe, some very nice end plugs can be machined with any decent timber. Some attach cork to these, not unlike a clarinet mouthpieces, to very good effect. I'm thinkin' about machining a couple of grooves for a couple of rubber seals or O-rings within the Acetal etc