From the desktop-devel list:
Two short articles are at this link:
http://www.asktog.com/columns/048GoodGrips.html
The first is a great example of accesibility bolstering usability for everyone, and provides some explanation of why and how this often happens. Its basic point is that both in the long term (old age) and at various short instances throughout our day (holding on object in the other hand, etc) well integrated accessibility-driven improvements can benefit everyone.
The second addresses the problems of branding taking precedence over usability, and how this is ultimately a marketing failure (Various Ximian people might do well to read this wrt to the evolution icon, menu entry, and title bar vs. the HIG).