I assembled mine from a router table leg set from Rockler Woodworking. They have the pieces for larger benches if you want. I used their matching heavy duty locking caster set on mine so I can roll it in and out of storage when I need to. All I did was cut some plywood for the top and shelves (and a lumber yard or home center will do that for you). Loaded down with brass, bulltets, and other reloading gear, it is very sturdy and works well.
Andy