SVG file format is a great way for creating resolution-independent images. If the draw node / drawing utils were to be suffciently extended, it could be possible to use SVG files for defining images to be drawn by the API instead of using raster images.

Note: there currently exist some libraries that take SVG files or commands as input and draw then on a canvas element, that could be used as partial code base, for example canvg: http://code.google.com/p/canvg/

I realize this is quite a heavy feature to implement, but I feel it would extremely increase the multi-resolution capabilities of cocos2d-html5.