I experimented with putting feet on the box as well as a way to raise the bottom of the box. If it had a mesh cut on the bottom of the box then that would be another way to keep the soap dry, but the soap box would still have to be on the sink or have another dish underneath it to catch the water. So I'm favoring the corrugated liner.
I'm aiming for this box to be three things: a soap box, a soap dish, and then a nice decorative box after the soap is gone. More than just a box, as notes Packaging Diva JoAnn Hines writing about David Graas' Not A Lamp,
I've been asking soap makers how many soaps in a hand-made batch. The Etsy folks say between 5-25 on bars on average. So there's my target range for a custom Etsy listing.