I'm thinking a hair could be found at a booth in a restaurant (or something similar). Do the test. If it proves a relationship, "leak the results" to the world. Someone will pick it up. Remember, it's not the nature of the evidence, but the seriousness of the charge!
You're right about that, for sure. But knowing Hillary's limitless vindictiveness and great power, and the fates of so many who've crossed her, you might have trouble finding someone who was willing to take the risk.