Hmmmm.. funny. To me accessibility goes far beyond allowing people with disabilities to use your website correctly.
And usability affects so much more than simple degradation.

Don't get me wrong, I applaud this effort. But it's not enough. Learn your Hijax, use it well. Netvibes is a good example of an entire Ajax webapp that still manages to be usable, with specks of unobtrusive JS. It's not accessible, but it's very usable.