Okay, I might be crazy but part of my profile used to have a check box labeled something like "I wouldn't mind being contacted by employers" or some such... and now it's not there. Did I imagine that?
Anyhow, you might want to contact Stack Overflow directly with your request. They might not be able to help you but they might have some service or feature in mind to help users out in this scenario.
I would certainly want to know if someone (legitimately) was interested in contacting me about a project. But that's why I include contact information in my profile.
When filling out a user profile, users can select "I'm open to employers (not recruiters) contacting me".
Considering that Stack Overflow offers a job placement service, it might be good-faith business gesture so place a job listing and inquire if they could pretty-please forward the listing to the user you are interested in (assuming the user authorized the communication in their profile).