I have noticed W3TC is allowed to host premium code in the WordPress Repo.
You may download their plugin freely from the WordPress repo, but certain features are paid, and you need a license key before you can leverage these features.
In their settings page, they have a "license" field, and when entered, premium features are unlocked.
I was under the impression that this is not allowed according to WordPress guidelines, and you need to seperate paid/premium code from the free code, in the WordPress Plugin Repo, as they do not allow hosting of this.
Please enlighten me.