Like in tables or text boxes, I would like to see the Rectangle tool (or polygon, or multi-sided pen tool creation) to be able to choose which side has a Stroke (colour &, thickness, etc).

I have a rectangle that I have cut one corner off of and want it to tuck into the corner of another rectangle. so I don't need the strokes to display for the bottom or side, but do for the top/ 45deg angle (right). Seems simple enough, but gets more when there are many sides to the shape... what's the limit you offer customization too? and what happens to the additional sides...?