In 2003, Panayiotis Zavos created "human cow" embryos that lived for several days and, theoretically, could have been implanted into a woman's womb. Researchers at the Mayo Clinic in Minnesota have produced pigs with hybrid pig-human blood cells

Personally, I wouldn't be too surprised at any human/animal hybrids they can create. Creating honest, intelligent politicians on the other hand, would be the holy grail of creation.

An interesting article on natural human chimeras I clipped a while ago.

A pop for Kore's unpopable clip