I too needed to provide a footrest on the passenger side and made an angled footrest with a bit of plywood and some battens, I glued on a matching piece from a spare car mat and it pushes into the footwell and effectively shortens it. It provides useful hidden storage behind it and the average non-Mog person wouldn't know it was any different.
It wedges in tight with battens to brace it against the original end of the footwell and I keep a few very useful things behind there, all out of view.
