Here's a peek at the teardown process including some good profile views of what the last repair was like. Plenty of glass there, but it looks like they layed it down in 2-3 separate panels with few if any sheets making the turn THROUGH the corner...mostly just lots of bulk epoxy in the joint that had started crumbling.
http://www.flickr.com/photos/12713306@N02/5971258523
http://www.flickr.com/photos/12713306@N02/5971820112
http://www.flickr.com/photos/12713306@N02/5971817742
-Josh