What you suggest is obviously theoretically possible, though the points would need to be properly validated and split into some supported geometry type (triangle strip, or whatever).
Another thing is how the resulting geometry would be textured. Since (at the window rendering level of abstraction) the system has no notion of a texture as such, but rather a collection of separate sprites or images. So you would need to expose the underlying texture. At this point you are dealing with raw geometry and textures - so you may as well do this directly and talk to the underlying API or engine.
In addition to the above, there would also be issues related to (but probably not limited to) hit-detection and clipping. If all images and controls are no longer quads, then you have to modify the system to be able to work with arbitrary geometry - which while not impossible, would most likely involve re-working large chunks of the system (for clipping you could no longer simply grab a Rect for the window, you'd have to ask for "the clipper" which would potentially be much more complicated, and to perform the actual clipping, what is currently a simple two-rect intersection calculation becomes a potentially complex masking operation).
I do not discount the possibility that such things will be added to the system, but I will say that if I, personally, undertook such a task it, would be way off in the distant future
However, if you or somebody else were to create such a modification - feel free to submit a patch as I'm always more than willing to look at contributed modifications to the system
When we called this function, and give a point list, It can generate the shape of this points and adds this shape to queue 
