About SVGPainter and SVGRender, now in SVG you can do some kind of graphic primitives containing more basic ones.
I mean you can define a kind of flowchart, that contains arrows, that are made of lines. You define the arrow once and put it in different places with different scales and rotations in your drawing.
Is it possible to do something like this in actual Painter?
You would need to make some storage of such composite elements.
IMO, you are starting at wrong end. I would take care about low-level SVG first (means shapes, fills, strokes). That would make it render most icons and similar stuff.