There are a number of western boot schools as well, while you specify work boots, the western packer boot was actually a redesigned work boot used by loggers, often referred to by name like WESCOs, White's, ect.... White has bought out WESCO, and produces several other brands of work boot. These are not the crepe sold stuff sold at walmart and other cheap junk store's, these are the pinnical of bootmaking tech, that loggers, firefighters, cowboys and ranchers will spend hundreds of dollars to purchase. So heres a few schools that can be found on the web.
http://www.bootmaker.com/dwswb.htm
http://www.merrellfootlab.com/institute.htm