>It seems to be most common in books published from (you guessed) DTP...
How can this glyph be common in DTP if it is not in any fonts?
Good grief...I've seen DTP users roll their own, using a variety of
software to mangle characters they didn't like the look of. It's
fairly easy to take the quote and mirror-image is and stuff it back
into the font file.
But from other correspondance, I am now more of the opinion that this
transgression is done by people using phototypesetters, working from
computer-prepared text. How on earth they manage to mangle it I don't
know. It was easy to slip when you had to load mats into the frame by
hand, because you could get them the wrong way round. It ought to be
impossible now to do accidentally, but I still see it. I'm going to
start collecting them, so anyone who comes across reversed quotes
please send me the reference.