Export to plotter via the parallel port
Tested with a Roland Camm-1 CX-24 on Linux via a USB-to-parallel cable.
Will also test with a Silhouette Portrait, however for that plotter our HPGL export currently does not yet work (http://www.inkscapeforum.com/viewtopic.php?f=31&t=33405&sid=fcb7fd452c2bc29863eec6d6ff6e030b).