just (nerve wrackingly) managed to do this on my Sempron socket A chip
. Tried to post pics but I couldn't figure out why they didn't appear in the preview
Multiplier unlocking was done by scraping the edges of the pit breaking bridge L5 , half filling it with modelling putty (I know I know) and then painting over the top with conductive silver paint.
multiplier changes are now available in CrystalCPUID, which seem to be real by CPU-Z, but sadly my MB doesn't allow undervolting, so it was a rather futile exercise
Still, worth finding out if it was possible though