Here's a bladesmith you can commission to build you a practical, non-ornamental dirk (scroll to near the bottom of the page):
http://www.olddominionforge.com/knives.html

Here's another guy:
http://www.scotiametalwork.com/page21.html

Getting back to the original topic: yes, to the right of the sporran, and in front of the hip is the traditional spot to wear your dirk....