Custom Shape Region Render - Marquee Drag Region

[RobH22]

I'd like to see a custom Region Render tool. I'd like to be able to drag a Marquee around a specific area that's not rectangular and maybe even add a 2nd irregular shape to a Render Region. I realize that shape would probably still be buckets that cross my drawn edge. But often times I have a area in one corner and an area in another corner that I need to rerender. I have to render a large, nearly full render, to catch both corners. If I could just drag around what I want to render it would prevent doing larger than necessary rerenders or doing two or three smaller region rerenders.