The builder will be finished with the Apple Campus before Apple ships out the next Mac Pro revision.
Well, they can't release the *seMP until it's time to celebrate the opening of the new campus. It will be, of course, of substantially greater diameter and lesser height than the current model. The matching SE **iRetina display we've been waiting for will have a round pedestal so as to fit within the ring, with forced-air vents around the circumference of the pedestal to cool the surrounding structure. A month prior to the Keynote, a Kickstarter project will be announced, promising to produce a CHiA landscape custom-designed to cover the rumored display's pedestal, with integrated, miniature LED lamp posts to ensure everything stays green. I leave it to someone else to figure out how to keep the thing watered without voiding AppleCare.
* If you didn't guess se = Spaceship Earth then there's absolutely no hope for humanity.
** i = incredibly, just in case you might think it meant "internet," "individual," or "investment-grade."
Edit: Sorry, I forgot to mention the curved ergonomic keyboard that nestles snugly against the outside of the ring, and the Magic Mouse in the shape of the parking structure.