I'm waiting until the next MacPro looks like the monolith from 2001 A Space Odyssey. The entire grey black slab could slowly pulse a über faint glow like the power light on late model PowerBooks. The idea would be to eliminate all indicator lights and make the entire monolith surface into the indicator that it's on and replace brightness with area.
I present to you, your next MacPro:
http://atypicalsnowman.files.wordpress.com/2008/03/2001_mono...
They might even have brainstorming sessions that go,