The Steller's Sea Cow would be a top choice for a "resurrection", but I think that the main motive behind that wouldn't be the idealistic one most of you favour: commercial harvest. With a constantly growing global human population, the drive to optimize the commercial utilization of all areas of the world increases. The icy shores and islands of the NW Pacific aren't optimal for productive industrial livestock farming or crop cultivation. The commercial farming of a huge, artificially (re)created mammal, however, that is well adopted to the harsh local weather and uses the local kelp forests for nutrition might be a novel, profitable business. According to Steller and other contemporary witnesses, the meat of the sea cow was quite tasty, which also prompted their extinction. Granted, I'm not the first one to come up with this idea, but you have to admit that if there's money to make, people with deep pockets are more likely to invest. For that very reason, Chinese businessmen would probably also invest in the recreation of Manis palaeojavanica to deliver more pangolin products to the market...