How do you get a public link to a file in Dropbox that isn't in a public folder?

Update:

This feature went live for all, without having to enable any sharing model or what not.

Previously:

Get the latest build of Dropbox, and you can right click any folder in your Dropbox and get the shareable link

Note: @slhck points that the Mac version doesn't support this yet - It does work on Mac. You will need to enable the sharing model feature on your account first (it is not enabled by default). The sharing model feature can be enabled by clicking here. Thanks to @emtunc for the update.

If get shareable link for any folder is not there for you, please click on this link to enable it. Once clicked, you'll get a brief notification and will be redirected to your Dropbox folder

Keep in mind that this change is permanent. We are unaware of any way to disable the sharing model once it has been turned on, but you can revoke the link by heading over to Sharing -> Linked Items and click on Remove.