I know that imagemagick is more raster tool then vector but convert.exe is awesome and it will be nice to see more supported formats. How about add two nice libraries libvisio http://www.freedesktop.org/wiki/Software/libvisio/ and libcdr http://cgit.freedesktop.org/libreoffice/libcdr/ ? Looks like these libs are up to date and have a lot of support from libreoffice project.
- Libcdr = Coreldraw cdr files
- Libvisio = Microsoft Visio files