If I am not mistaken, the Hunter 31s came with a single deep stainless steel sink. That one looks like a PO might have changed it to a double, albiet shallow. The H34 came with deep doubles.
With that being said, I would start at Home Depot or Lowes. There are small bar sinks, deep but they might be singles. I think you can shop around and find something that should fit in your opening. Also Google RV sinks and you may see something appropriate.