Have no fear, Dear Hubs came up with a solution to the rescue. With as little as agreeing it was a good idea, Dear Hubs swooped into action and surprised me by creating a cover for the hearth that is stylish and perfectly safe.
Since it wasn't my project, I don't (a) have pictures of the steps and (b) only have a rough idea of how he did his magic.
Cut 1x1's (or have the store do it) to meet your measurements for the sides and front. Flat plywood board is used for the top. Screw the 1x1 onto the plywood. Cover the entire "box" with carpet padding foam and staple into place. I chose a neutral linen muslin to cover the entire thing so it blends nicely with the stone and the decor.
Now, less to worry about when Baby B tries his daredevil stunts! Thanks Dear Hubs!