Sound like a shot in the dark. You might want to consider asking them first if they have any interest in Genealogy or have done any Genealogy research. A DNA test without a pedigree chart is useless, in my opinion.
Here's an idea. SMGF travels around to different cities having family history fairs. They are having one in Richmond Virginia May 16-19, 2007 - http://www.eshow2000.com/ngs/2007/
. Start with calling the Duggers in Richmond Virginia and encouraging them to go and while there visit the SMGF booth. They can submit a sample and their 4+ generation pedigree chart. Then you can call them back after the fair and see if they want to join your surname project.
Here are other locations:
Pocotello, Idaho - May 19
Ottawa, Ontario - June 1-2, 2007
Burbank, California - June 8-10, 2007http://www.smgf.org/events.jspx#Event81
Here's a current list of events as of May 15, 2007.