While the rendering works fine as is right now, I can guarantee, that the icons as they are will also be correctly rendered by librsvg. I've myself cursed librsvg for not rendering my icons properly, but it always has been a matter of gradients and transparencies within icons that at some point were created with CorelDraw.
Attached is a screenshot of Inkscape next to its younger brother from the Gtkmm codebase. You'll notice the icons do render a bit differently when passed through librsvg (they're not as crisp). And the only icon that has a problem with librsvg is fill-stroke.svg, as you can see in the screenshot.
Text doesn't work either, but heck, this is nothing to care about for the inkscape icons.
Actually, text does work in newer versions of librsvg. My original reason for coming to Inkscape was to layout a broadsheet newspaper. The icons created by Nautilus of the layout SVGs is quite beautiful, actually.
I don't think that the approach of handling over the icons to librsvg does definitely involve ripping apart the file. It might as well be possible to first extract them from the file into a temporary svg and hand this one over.
Originally I asked if someone could script the ripping apart of icons.svg into separate files, so the creation of separate files could be automated, and so icons.svg could still be used as the source of all icons, with the Gtkmm build scripts automagically tearing it apart into the files it needs.
But I guess because of use of clones and other shared resources with icons.svg, ripping it apart into separate SVGs is rather difficult.
Another advantage here would be that the icons will fade in with the rest of the desktop a little better. My theme is making use of icons having lower saturation and opacity in normal state, higher in prelight state and very low ones in insensitive state. Therefore even for markers and such, I'd make sense to have librsvg render them. Right now these preferences are not adapted by Inkscape, which is a pity IMHO.
Those sorts of things have more to do with using IconFactory than they do with using librsvg.
librsvg is convenient right now only because I can simply pass a filename of the SVG icon to IconFactory, with no extra effort or programming. librsvg is used by IconFactory/gdk-pixbuf behind the scenes without anybody thinking about it.
