Lonesome George was the last of the Pinta Island subspecies (not full species). The Galapagos are a marvel of evolution in action, and the tortoises on each island are distinct subspecies, unique and different from each other. The death of his kind is laid squarely at the foot of mankind, and in spite of our growing enlightenment, and best efforts, we could not take it back.
George's problems with breeding suggest that even if a Pinta island female were found, he would not have been able to propagate the subspecies.
Pinta island is undergoing restoration, with efforts underway to eliminate all rats, goats, and other introduced species, and the vegetation of the island is recovering. I had heard of some vague plans to introduce a tortoise subspecies with similar characteristics from another island, to fill the ecological niche left open.
The Galapagos being what they are, if we allow it, perhaps the introduced tortoises will become something new as well.