GIMP is correct. CCIF doesn't really have members, but I've been a participant since day 1. Not only had I never seen the document until this morning, I'd never even heard of it until the Microsoft post.

Amazon's EC2, 3tera's Applogic, Flexiscale, GoGrid, etc all run Xen.

Mostly correct. There are a few OS's that don't deal well with para-virtualization yet. You may be able to run them, but the IO will be incredibly slow.

Not all cloud computing providers are ignoring this issue. You can already get AppLogic service in many countries around the globe for just these reasons.