I've finished up the second round if icon loading cleanup. First was to get things going with stock images http://library.gnome.org/devel/gtk/stable/gtk-Themeable-Stock- Images.html
This second pass was to get the newer icon theme (added with GTK 2.6) http://library.gnome.org/devel/gtk/stable/GtkIconTheme.html
That second part allows for the newer theme sets of icons to be loaded. These include the Tango icons. Probably the most important part is this now allows Inkscape to follow a standard look with other apps by using shared icons. In order to do this well we need to use standard names and standard concepts as much as possible. With my recent checkin I switched three icons over to standard, but there are still two main things to do
First is to see if we can use any existing standard icons. The base spec with proposed standard icon names is at http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec- latest.html The standard icons out in existing themes, though, don't use all of those. Such themes are usually under /usr/share/icons/* or the equivalent. A few I have here are "highcolor" (the fallback default), "Human" and "Tangerine".
The main second thing is to get graphic-app specific icons that are not listed in the default set figured out and assigned names. The Tango project had started this under their Art Libre set. http://tango.freedesktop.org/ArtLibreSet If anyone can take a look through there, that would be a great help. And more importantly if anyone who uses other apps such as GIMP, Krita, Blender, etc. could take a peek at what could be unified that would be a huge help.