Implicit Bias in Networking?

I have recently engaged in helping my son’s college roommate look for a summer internship. She is an awesome person, with great personal qualities, including being a very hard worker. Some of her quantitative measures, such as overall GPA, are not as high as some HR gatekeepers would like to see. But, I have seen over and over, as a hiring manager, that the non-quantitative measures are both critical to future success in the position, as well as very often overlooked by these gatekeepers.
Of course, this is where having an introduction through a network of connected peers is vital. This is the service I’m providing my son’s roommate — I am reaching out to hiring managers and leaders in software companies in the area, and personally vouching for how “kick ass” this young lady is, and how I know for a fact that she would be an asset to their teams. I don’t think of this at all, as favoritism. It is simply a service I provide to my network, to make introductions, and to point out these qualitative (and important) factors, that often get overlooked by hiring systems that are way too quantitative.
So, I’m a big believer in the value of these personal connections. However, here’s the rub. It is biased towards the types of connections in my network. If I don’t have diversity in my network, then I end up only making these introductions for people that are like me. This concerns me, not just because of philosophical reasons, but because I am causing real potential talent to be overlooked. So, how do I avoid this?
The only solution is, of course, to find ways to diversify my network. (By the way, I actually have a relatively diverse network in terms of nationality and gender. But not necessarily in terms of ethnicity.) I am actively looking for networking opportunities and events that will bring me into professional and personal contact with people and demographics not currently well represented in my network. I have found a few good options, via meetup.com, and local minority Chambers of Commerce. But, I am open to more suggestions. Any ideas out there?