Built the ultimate downdraft / dust collector today. A simple box 26" tall 24" wide and 34" long, and mounted a gas furnace blower motor inside. Used pegboard for the top, and cut a 4" hole in the back for additional DC for my miter saw or router. The blower motor runs off of 110V, pushes 1000 CFM and is much quieter than my shop vac. Going to add some 10" flex duct on the front so I can make sure all the dust goes outside. Total cost: 25.00 for plywood, 1 pot of coffee, and an enjoyable day in the shop.