Looking for advice on finding prior service developers with clearances (current or expired)

I would recommend posting on veteran pages on Linked In, or on the Dysfunctional Veterans page on Facebook. Also, Veteran Insider is a group in Texas focused on helping vets get jobs, speak with Brian Rucker and he can find you some people.

Thanks for the feed back. I have reached out to the National Guard career liaisons and local reserve centers, but a lot of the talent I am looking for will have transitioned several years ago.

I am none of those, I worked in various capacities but like the previous respondent I too am retired. That being said, have you considered Reserve Centers? They get a lot of freshly separated as well as drilling reservists who might be in the categories you are looking for and it would make their job easier because they can help point freshly separated or working folks to new positions via your firm. I know when I first separated one of my concerns was employment.