So this is where you find a besom (a real, workhorse deal of a besom and not a Wiccan altar besom):
Moontree Forge & Broom on Etsy - her long whisk brooms remind me those Indonesian street brooms; this is the one I have (and love).
Justamere Tree Farm - seen in Martha Stewart Living 10/2009
Hida Tool & Hardware Company
Building for Health Eco-Center
Or you can make your own.