While I applaud the focus on diversity and think that it is important that organizations do not discriminate based on nationality/gender/whatever, I hardly think this is a serious concern for smaller companies looking to grow. While I don't believe that discrimination never happens, to me identifying a pattern of discrimination is something that is substantively more achievable with a larger organization than it is in a company with a size under 25.

Ultimately, what I'm getting at is that your question is approaching things from the wrong angle in my opinion. Companies should be choosing whomever best fits the role while ensuring they are not discriminating against minorities (either consciously or subconsciously). Setting out from the start to focus on diversity hires sounds a little too much like trying to fill quotas for my comfort.