The workbench top was built using a torsion box design. This allows for a very flat top that tends to stay flat.  The top surface was two layers of 3/4" MDF then a 1/4" high density surface, then Formica. The base is made using the torsion box design as well.
Maple was used to cantiliver support for the vise. 
This creates a secure place to lag screw the vise and returns strength to the table where material was removed to accommodate the vice.
Finished Bench