I'm not selling them but I did once make a coconut cave for a friend his fish loved it plus it was wooden so his little sucker fish loved to give it attention. All I had to do was chop a coconut in half carve out its innerds, boil for a while wait for it to cool then put it inside. (I also took off all of the hairs since he said he wanted them gone)
You could try making one incase you can't find one to buy