I know we kept this in mind for my dad who had colon cancer with liver mets. B/c the liver isn't the primary site, the patient isn't eligible for an anonymous liver transplant b/c the cancer could attack that new liver, but I do know if you have a large enough liver and you are compatible, there are more and more cases of this taking place....you are right, it is a very viable option if the rest of the cancer can be stalemated.
Best of luck