[Inkscape-devel] DOM SVG Canvas

I want to write a mapping/GIS application. I was hoping to find an 'SVG canvas' library that I could use to render the graphics. Librsvg is not ideal because it simply renders the entire SVG document at once. Rather I am looking for something that watches a DOM tree and renders changes as they occur. Do Inkscape or sodipodi have any such internal structure, or could they be used as a basis for such a thing? Seems like people are going to be writing a lot of low-level SVG rendering code otherwise.