You only need one Linchpin. That's all you need to start. And if you can spot him and support him, he'll make waves in your organization. If you can find her and give her the leverage to make change, she'll infect everyone else with Linchpin goodness.
But guess what? If you can recognize the Linchpin and bring yourself to backing him, you're a Linchpin too. And so it grows. Recognition is the key here. So be on the lookout.