Grizzly has iGaging scales at very good prices. The 6" that they stock is on sale for $22.95. The summer sales flier also lists 12", 24" and 35" lengths.
Yesterday I received a new "Metal Work Accessories" catalog that listed the 6" scale but none of the longer lengths so I wonder if this is a one time deal?
http://www.grizzly.com/catalog/2011/SpringFlyer/52Joe