"When's the last time anyone has heard of someone dying from a vitamin overdose?"
Don't know about dying, but several arctic explorers developed an exfoliative dermatitis from (IIRC) vitamin A toxicity after eating polar bear or walrus liver. Also found this:
"In 1913, Antarctic explorers Douglas Mawson and Xavier Mertz were both poisoned (and Mertz died) from eating the livers of their sled dogs during the Far Eastern Party" Wikipedia entry.
So there's a fatality.