Gary Humphrey makes cylindrical metal-bodied whistles with black acetal mouthpieces. This is the whistle that I'm currently playing and am very fond of it. His whistles mimic the look of the Generation / Feadóg style mass-produced whistles, but with the tone, tuning, and stability of a professional high-end instrument. Prices are reasonable (~$90 for a standard D) for a handmade instrument, but if you're looking for a quality whistle at a good price, make sure you order one soon since word is spreading about Gary's work.

UPDATE: Gary is unfortunately not taking any orders at the moment but I'm going to keep his site linked here in case he opens for business again.

Whistle Makers