Dover Inlay has opened again as Dover Design, LLC, owned by a previous employee of Dover Inlay.
They still sell holly inlay.
www.doverdesignsllc.com 301-733-0909
Another source of holly inlay is Lines Unlimited in North Carolina
www.linesunlimited.net 336-996-6603 I spoke with Kyle
Another good inlay source is Inlay Product World, Inc. They do not sell holly inlay, but recommend using white sycamore instead, which they do sell. They tell me that their products come from Spain.
www.inlays.com 877-464-6529