On a side note if you are looking to open source it I might contribute to it in my free time. I've found a few possible products^ since I made this post and they seem to be actively maintained so I hope that I can avoid spending much billable time on this. But the barren landscape makes me feel like there have to be other devs/companies struggling with this problem so I think as an open source project it could gather steam.

^The most promising ones I've seen are pelock and intellilock (not endorsements, haven't evaluated either one yet).