Finally have some extra time to load up some more pics of the build!
I drilled through the rock with a hand drill, just normal bits, and inserted the acyrlic rods.
I used three acrylic rods to support this main piece. You can also see some of the clear zip ties.
Another view.
Here is a view of the underside. I used a heat gun to bend the acrylic rods to get them to fit the holes I drilled. The curves help ensure that the rock can slide around also. The rods are completely hidden in the final product.