Pretty much any customisable unit frame addon should be able to do this like Shadowed Unit Frames, Discord Unit Frames or STUF etc.
Essentially you create two images, presumably circular with or without the center cut out depending on the look you want. The grey one is the background. Then, over the top of that you place the actuall bar image that will resize. On top of that you place the circular portrait.
You can see something simliar in screenshot 9 of the
DUF configuation pack athough it's using semi-circles for health and mana.