>>>I've read about people putting counter-top laminate (Formica) on the inside of the centerboard trunk to give the centerboard a nice, slick surface to rub against.
>
The specified epoxy surface, sanded smooth, is very very very hard. I would place a tall wager that it will never wear out.
A coating of epoxy mixed with graphite will make it harder still, but it's a ton of effort.
Somewhere I have a can of powdered Teflon that, mixed with epoxy, might make a really hard, slick surface.
But based on five years of sailing PocketShip #1, there's no sign that the smooth epoxy faces of the centerboard trunk are wearing at all. One of these days I'm going to hoist my boat with CLC's forklift and get a look at the centerboard to see how it's doing. It's hit bottom everywhere from Maine to Puget Sound and many spots between.