[wool_gather]

This seems similar to the "hire from your network" that was mentioned in the OP. Or, to rephrase, how do you find/target these developers?

[andy_adams]

I mean outside of your network - people you wouldn't normally get referrals for. LinkedIn in a starting point, then researching an individual (Github profile, Twitter, personal website, etc) to learn more. This will obviously only work if the dev has a public life.

[mbrameld]

Do you use any open-source projects? Reach out to the contributors.