If you are talking about the ones that are preprinted with lines for all the load info I have seen them at some truck stops. The only other place I have ever seen them were at company stores. Kind of pricey as far as I am concerned.
IMHO you are better off just going to Wal Mart, Kmart, Staples, Big Lots, etc and getting yourself some pocket sized spiral bound notebooks.
You can order the Driver's load notebook direct from JJ Keller.
Driver's Load Notebook Detail - J. J. Keller & Associates, Inc. 039-B