How to 9-Slice a 2D Sprite without Plugins?

I know there are many toolkits and plugins that can help in the creation of using 9-slice sprites to preserve borders when scaling.
Conceptual example:

This seems to be an unpopular question.
Does Unity3D 4.6.1 or below have any of these features?

My project is far along to the point where it would be considerable work to implement a new 2D api.
Also, personally it’d be a shame to have to use another API considering Unity worked hard on making 2D available.

Is this possible?
If not, I guess plugins are my only alternative?
If so, which ones should I look at?

This was introduced in Unity 4.6

Unity5.5 alpha has this feature