I assume you've talked to US bike shops that specialize in Dutch bikes like
www.mydutchbike.com/, or Chicago's
https://jclindbikes.com/? They might have a handle on something similar to the Fryslan.
__________________
"I had a great ride this morning, except for that part about winding up at work."
Bikes so far: 2011 Felt Z85,
80's Raleigh Sovereign (USA),
91 Bianchi Peregrine,
91 Austro-Daimler Pathfinder,
90's Trek 730 Multitrack, STOLEN:
80 Schwinn Voyageur (Japan)