Rotoscope node and paint node inside shader editor

It would be great to bring the rotoscope/mask nodes to shader editor so we can merge some textures (using mix rgb ) and mask them by drawing a spline shape (rotoscope).

Also make the whatever we paint an image texture (in image editor) to be available in shader editor as a node ( a Paint node). Of course the 'live paint' will be slower to calculate. But we can overcome this by adding something like diskcache node or write node ( like in nuke) so we can write it to disk while we still maintain the capability to edit /modify the paint stroke.