Apart from the sudden surge in trends and fetishes, some people here have a point as to whether or not it would be ethical.
However, I would point out that crossbreeding and splicing genes in things (even plants) constitutes the creation of new life that nature did not create on it's own. Ethical concerns are certainly an issue, but it would seem like they might be more along a religious boundary rather than simple common ethics. I won't attack any faiths in particular, but I will use the phrase 'Playing God'
It's an interesting phrase to use, as we already 'Play God' to some extent. We've bred dogs to fulfill certain roles in our society, we've bred roses to have different colors. It's all the same act of 'Playing God', it's just not as prominent as this would be.
Another person said that it would violate the new creations 'rights'. I don't mean to be rude, but knowing our own spotty history when it comes to new arrivals and their 'rights'. I would like to direct attention to the "building a Mosque near the World Trade Center area." Muslims are the latest in a line of cultures/minorities/ etc. that have been persecuted. It was once the Irish, who now are as American as apple pie and such, there were the Puerto Ricans, and not to mention another very prominent group, the African-Americans. All these groups came to America, but their 'rights' had to be grandfathered in over time. Much like these new additions to society would have to be. Heck, it might even get violent were they to become public.
I'd say, in a perfect world where people tolerate one another easily and openly, it would be a wonderful thing for many people, and if not wonderful, it would at least make walking down the street very colorful and interesting. In our existence, it's more likely to cause tons of issues that won't get resolved until centuries of exploitation and abuse die down to where it simply becomes normal to subjugate them, or it becomes normal to have them around.