resvg [1] is an SVG rendering library that aims to replace librsvg and QtSvg. It supports multiple backends and designed for edge-cases. It doesn't support all SVG features yet, but it's already has the best support for edge-cases [2].
In the latest release, I've added a Windows Explorer extension [3] which can be used to render SVG thumbnails via resvg. Previously, the only solution was to use SVG Viewer Extension for Windows Explorer [4] which use Qt4 SVG module, which is very primitive and outdated.
[0] http://www.nomacs.org