Selective breeding is also known as "artificial selection", which essentially means "made by humans", thereby, what is possible is up to human imagination, endeavor and how much research and disposition is assembled in order to achieve a particular breeding goal.
So, nowadays that the study of the genomes is advanced, its a matter of how much time, energy and resources are combined to lay out an assignment that sorts an specific set of instructions needed to create a particularly desired organism (or trait, in this case). Accordingly, any of those traits mentioned above could be achievable by modern selective breeding.