Green, Jonathon Slang thesaurus Penguin (1999)
has "blessed" as one of the entries for "cursed" - after "blasted" and "bleeding" and before "blithering."

And this does concur with my own experience - you put something down and can't remember where, so ask the world in general, "Now where on earth has the blessed thing got to?"
It isn't so common in UK these days, when rough and rude swear words are on nearly everyones lips, but certainly when I was a youngster, it was very common for adults to use that form when children were present.

EDIT: the pronunciation was always, "blessÚd