Light Blocker Implementation

I'd love to see light blockers exist as a tool in cycles. They exist in renderers such as renderman but atm I'm having to create a custom solution using planes. This works for basic blocking but is missing things such as the ability to have a soft edge on the blocker.

This tutorial gives a quick run through of how they work in renderman as an example: youtu.be/vWGxo_P__eE

I've spoken to a few of my lighter friends and light blockers are something they always mention as a must have if they were using any renderer. I think cycles should implement this hopefully sometime soon.