When I left p&p, one of the teams I was considering was the Acropolis team. It would've been an opportunity to go do CAB as a fully supported development environment enabled thing, rather than just a raw framework from a few people. I'm glad they've announced it now, so people can see the direction that Microsoft is headed in. Glenn Block from p&p has a post about the future of the smart client p&p deliverables in light of this announcement, too.
I wonder if there's someone on the net who thinks he can re-implement Acropolis in 15 minutes? ;)