we've just had the discussion at work and have concluded that if the animal is stray/rescued/injured/unwanted etc and would be killed without an owner then this is OK, however if the animal has been bred to sell then that is not OK as it goes against vegan beliefs of not using animals for commercial gain.
Of course there is the argument that no one should buy a pet whilst there are so many to be rehomed, but that's a different story.
Thoughts, have we missed something?