Mike from Sidekiq kind of does this with his Pro [0] version -- offering a "more reliable" job queue via Redis' RPOPLPUSH among other features. He still uses license keys and a private gem server to distribute the premium features, afaiaa [1].

[0]: https://sidekiq.org/products/pro.html

[1]: https://www.mikeperham.com/2016/05/17/commercial-gems/