Gary Chambers is the creator of the Polymorph project - a skinnable UI look currently supporting Watery, Vista, Old Squeak and Windows 2k look.
It is available for Squeak and the default for the Pharo image.
Gary (or GazzaGuru) works in a company called Pinesoft and he posted some new screenshots of their latest application built with Pharo. Read more here and here.
BTW: If you want to customize the Squeak VM for an own Smalltalk based product I've created a short howto which is (thanks to Andreas) now available on squeakvm.org