I thought about a tutorial or a step-by-step but EHCI controllers vary widely by platform, and going with the "least common denominator" means doing it for x86... I could never convince myself it was worth a blog post.

Maybe if the RPi becomes a favorite for OS development, I might do it. You could always poke around on http://osdev.org and see if you find some useful stuff there. :)

Some controller better than no controller.

I was allegedly a kernel engineer at one time but never go to do any kind of development work, so this sort of thing intrigues me greatly.

What hardware did you have?