Nothing very rock n roll, but I’d like to see:
- not so much a piece but maybe a Kinetic sand collaboration with pirates digging up treasure
I think with sand that actual sand would be better for digging treasure up. Have a solid sand base as you mention but place it on a sand area or perhaps have another sand base which is a frame with actual sand in the middle. The frame could have a detachable floor so you could fill it up with sand for use indoors and keep the mess down or take the floor out and use the frame at the beach and dig as deep as you like.
Looking at your list of possible steck parts reminds me that the pirate prison came with a couple of nice pieces - door with hole in it for passing things through, a whole wall of bars and a brown coloured cap that covered the top of wall sections.
This thing:
https://playmodb.org/cgi-bin/showpart.pl?partnum=30-09-5310The waves for the ship would actually make a nice regular piece to clip to the bottom of the hull.