My XFX Radeon HD 6950's fan also seized. I picked up
http://www.amazon.co.uk/ARTIC-Coolin.../dp/B005I9IM4E. It doesn't look like much, but it ran cooler and quieter than the stock fan, I was quite impressed. Only problem is it takes up two slots below the GPU (so three total counting the card), so if you have a smaller case or a lot of add-on cards installed, or Crossfire with only a one-slot gap between, it won't work.
EDIT: Whoops, didn't realize I was on page 4, sorry for the kinda-thread-necro. Still, this is a seriously inexpensive cooler that will keep the HD 6950 quite cool.