Oh, we have plenty of horror stories, but nobody seems to be drawing lessons out of them.
The nearest I found was the Maintainability pattern language, which is worth a read. But even that document is too generic to be useful in the trenches.
I am still looking. If I don’t find anything, I will try to codify my own experience, but surely somebody else has done at least some of it already.
BlogicBlogger Over and Out