So @r.david.murray, it would appear you were right :D Really, I should have looped through each method on str(), and wrapped them all to see which were being called, but lesson learned I guess.

Sooo, I guess now the question is, can we possibly get a vote on having a feature which disables this functionality from the opener level. Something like:
opener = urllib2.build_opener(urllib2.HTTPHandler(debuglevel=1, keep_original_header_case=True))

But obviously a less tedious attribute name :)

In the mean times, if anyone else comes up against this problem, the code I pasted above will work fine for now.

Cal