Yes I thought that Farm Tek flooring was excellent and not sharp or hard on puppies' feet. It was tough plastic and looks like it would hold up well.
For side panels, doesn't Tractor Supply have a 2 inch square 6 gauge heavy mesh in panels for horses maybe? I'd think that would work very well for the sides.
Just took a look online and Tractor Supply has horse panels 2" by 4" mesh 6 gauge steel panels 5 foot by 16 foot --
http://www.tractorsupply.com/tsc/pro...t?cm_vc=-10005
Those should be good for sides.