How about plating the cast iron? A good layer of copper/nickle and a
flash of chrome should protect it nicely and look good for those that
like the shiny chrome look (personally I don't). Skip the chrome flash
and bead blast the CI before plating to get a nice satin look. The
nickle plate would be pretty hard so it should last a long time. A
thick plating of hard chrome would be even more wear resistant. Good
metalworking machines have hard chrome on wear points for long wear.
Rusting should not be a problem with plating.