australia
Although the alleged victim has not been found, this case from the upi.com archives dated 25/09/1986 is worthy of note (emphasis mine):
A woman jailed for murdering her husband had her conviction reversed when a witness testified she saw the man on television -- in a crowd at a cricket match -- three years after he allegedly was killed.
The New South Wales Court of Appeal Wednesday overturned the murder conviction of Margaret Burton, saying the case against her relied on a web of circumstantial evidence and that the new evidence provided reasonable doubt of her guilt.
Burton, however, still must complete an 8-year sentence for conspiracy to commit murder.
She was sentenced to life in prison on Nov. 8, 1984, for the May 1983 murder of her husband. She and Ronald Burke, a close friend, also were sentenced to eight years in jail for conspiracy to murder her husband, Peter Burton.
Peter Burton's body never was found.
At the appeals court hearing, Judy Edmonds testified she is sure she saw Peter Burton in the crowd at a televised cricket match in January.
Edmonds was shown a videotape of part of the cricket match and identified a man in sunglasses as Peter Burton. She said she was a close friend of his.
Another witness, Jan Dyson, told the court the man in the videotape bore a remarkable resemblance to Peter Burton.
Lawyers for Margaret Burton argued before the appeals court her conviction should be overturned because the prosecution failed to prove Peter Burton was dead.
Appeals Court Chief Justice Sir Laurence Street agreed, saying it is not for the court to decide whether or not the person on the videotape is Peter Burton, but it is the court's responsibility to determine how a reasonable jury would have regarded the new evidence.
murder conviction victim alive
turns up lots. Here is a 2009 CNN story listing six.