Yeah, everything is Koninklijk there.... :)
But seriously, I've never seen a dutch silver or gold coin yet, and I've seen a lot of other ones. However, its possible that they made some for other countries and it wasn't mention. Thinking about it, its kind of strange that a lot of european countries are not present in the coin market, at least not in the investment coin sector. For example the French, or the Belgians, Spanish and Italian, and many more. The only really easy to find are the British and Austrian, and a few German ones. Oh, and Swiss, too. What you really find for a good price are Australian, Canadian and US, RSA, Fiji and other far away places.