Here is my first hand reporting on the new arena when I was there Dec. 27th:
http://newarenaatseattlecenter.com/
They are basically keeping the roof from the Old Key Arena (near the Space Needle) and shoving a whole new arena under the old roof. I'm not so sure what is so great about the old roof - doesn't look that special to me. Looks like they have a ton of work to do to be ready on time.
They are clearly angling for an NBA team.