if you go to beardeddragons.org and look at some of the past enclosure posts, they'll give you pictures and idea on how to make a custom rock wall. With grout and polyurethane and big messy words like that. I used to have a link to a few different sites that made showed you how to make custom rock walls, they had 'caves' and ledges. It's a pretty cool project. I am sure if you ask they'll direct you in the right direction.