Would is be possible to add the option to change the background color and alpha and possibly keep the border separate? For example, I have a static dark gray color for my raid frame health bars, and it would be nice to have the background, let's say a light color. All this while having a 1-pixel black border like there is now.

There is no permanent border on my frames. Just a background. And to answer your next question: no i am not changing that.