I have a D by Michael Burke, Delrin-lined, and with an O-ring to ease tuning. It's not quite as well tuned within itself as it should be for the money, and the bottom note is weak for an instrument of this class, but the Delrin lining works a treat.

I'd still be insterested to know of any manufacturer turning out whistles in E (as opposed to low E) - not counting those who might do it to order, which is what I assume Bob is referring to.