Neowin has some screen shots of the alleged 4051 build of Longhorn. (A number of different Web sites are calling this the "PDC build" that Microsoft will distribute at the Professional Developers Conference. Microsoft is denying to comment.) Neowin is reporting that 4051 will include a new "theme" called "Slate" (which does, indeed, look like a slab of slate). Neowin says Slate will likely replace the "Plex" theme that has been part of previously leaked Longhorn builds.