I’ve started a new project at https://github.com/ianturton/ShapefileViewer to allow people to style shapefiles and export the SLD and the layer as SVG. I’ve written a brief blog post about it at http://blog.ianturton.com/geotools/mapping/cartography/sld/2015/07/04/Styling-Shapefiles.markdown.html
Feel free to fork and jump in, I have no plans for this to become a GIS as UDig fills that niche nicely, but I’m happy to expand it’s functionality to make it a more useful utility.
Ian