There are some good photos and history of a 2.4 m diameter turbine with corroded magnets at the Build Your Own Wind Turbine site in Ireland. A paint job on some corroded magnets in 2009 and we get to see how effective this was.
The story begins in 2009 with this servicing workshop. The magnets were quite badly corroded. 
but they got cleaned up and painted as below in the next installment of the story here.
Here is a paint job they did in 2009. Jump to 2011 and the turbine is revisited.
The alternator is pulled apart and this is what it looks like:
Not too bad really considering what it looked like in 2009. I would probably have replaced them but they are very expensive. There is another story here.
And a discussion on the Fieldlines Board covering the issue of neo magnet corrosion.
Finally some photos on facebook here. Not all completely on the magnet topic.
