Thinking about extending gradients (new pluggin or possible without?)

Inspired by SPA and their custom light and shadow tools!
Ive been thinking about how to quickly create regions with a gradient as a border, that stretches out and fills the border width.
Or an other approach could be to use two regions to create a contour based gradient.
What would be the best way of doing something like this, any thoughts on this are welcomed

Just realized this is exactly what gradient layers does! I didnt even think about looking for a vertex width in gradients until just now. Amazing!