Interesting to see this interest in Dutch bikes from so far away! Can't be easy to find something overthere. The 60's and the 70's must have been the best period for small frame builders over here in the Netherlands; it was common for crit racers to have your own frame build by a local builder.
from mid-80's on people started to buy more off the rack, got more interested in Italian bikes, and so many small builders went out of business.
I got my 'Visser Vainqueur' built in 1981, and I still have it. repainted three times now, and converted to a SS. It was built by someone who was known as 'Witte Ko' (passed away about 10 years ago), a somewhat secluded older man living in a small village about an hour from Rotterdam, where the Visser shop was. The owner of the shop did not allow customers to go see Witte Ko! He built this frame for me, no measuremnts except inseam were taken, I was just asked to ride in front of the shop on my bike of that time, once relaxed and once full speed. The frame was built and fit perfectly.

Zieleman is an Amsterdam builder (you know that probably), Bontekoe is Den Haag. More names from that time are Reus (near Amsterdam), Sirocco (Zeeland), Brands (Amsterdam). Of course most people know Gazelle (Champion Mondial) and Batavus (Criterium, Professional). Would be a nice experiment to see if anyone could score a bike from the other side of the Atlantic! Many Peugeots there too!