Gold's Delicatessen mail order on line has Hebrew National Kosher Salami, and also Hebrew National Kosher Hard Salami:
Scroll down to "Meats By The Pound"
The Mill Basin Kosher Delicatessen also has large Hebrew National salami on line: http://www.mssk6.bizland.com/store/
The Park East Kosher Butcher has a large selection of deli meats (and other things) but don't seem to carry Hebrew National brands. Still, there do carry Kosher salami's, so I thought you might be interested:
Hope that helps!