quotes from another article on human animal chimeras and possibility for unlimited compatible organs avaialble for transplantation

-By modifying genes, scientists can now easily change the DNA in pig or sheep embryos so that they are genetically incapable of forming a specific tissue. Then, by adding stem cells from a person, they hope the human cells will take over the job of forming the missing organ, which could then be harvested from the animal for use in a transplant operation....

 “We can make an animal without a heart. We have engineered pigs that lack skeletal muscles and blood vessels,” says Daniel Garry, a cardiologist who leads a chimera project at the University of Minnesota...

One reason is that if his iPS cells develop inside an animal, the resulting tissue will actually be his, a kind of perfectly matched replacement part. Desperately ill people on organ waiting lists might someday order a chimera and wait less than a year for their own custom organ to be ready. “I really don’t see much risk to society,” he says..-source technologyreview

Interesting snippet from another article on human animal chimera research.   A possible near term solution to the problem of organ transplants. 

Very very interesting things could be done with chimeras, I see a lot of potential.   You can eventually not only design these to be compatible with humans but you can use these to research the function and effects of genetically modified superorgans.    Given that rat mouse organ chimeras have already taken place, it would be interesting to see if replacing one of a few organs with the longer lived version organs have any significant effect on lifespan. 

Another possibility is that if the mother animals are suitably modified they might even be able to function as living artificial wombs.    Accelerating the arrival of artificial womb technologies.  Artificial wombs would when combined with a few other techs allow for same sex couples to have children irregardless of their biological sex and it would also help enable single individuals to reproduce, and would free women from having to carry the delicate baby around for 9 months everywhere they go.