Using ALCO’s prototypical design, Mainstream site-adapts each location using its in-house CAD and Design capabilities, a key factor in the Company’s construction scheduling success. Currently, Mainstream has four ALCO stores under construction in Georgia. Duckwall-ALCO Stores, Inc. (NASDAQ:DUCK) is a general retail merchandiser serving secondary markets with more than 250 stores operating under two brand names, Duckwall and ALCO.