Ziplink Mattress in the USA

Any advice on where we could purchase a new king size ziplink mattress in the USA? We actually bought a used one a few years ago, and it has been the best bed we could ask for. "Kingsdown Ziplink Mattress" I had no idea they were so rare here in America. We never asked the seller where they got it from. We would like to buy a new one but can't find them anywhere.. Is an overseas delivery possible?