Rear bath walls?

[Art Culinair]

I would have searched the forums but my phone is not letting me use the search bar. I have gutted my rear bath and am in the process of fabricating my shower pan however I cannot find a suitable interior skin replacement for the bathroom. I have looked at wacky wood, pebble board and ever lincrusta, but I just can't seem to find something that will do the trick at the big box stores... Any suggestions?

[Living31]

FRP fiber reinforced plastic

Available in all big box stores. Google it for installation vids/tips

Good luck