My grandfather fought with the Canadian 8th Recce Regiment (14th Canadian Hussars)and every photo from training and in NW Europe - shows them using a NB4.
I am on a life-long hunt for a NB4 for me and my grandson to enjoy - in period correct WWII livery. I am totally comfortable with the price estimates for a period correct bike, but I have literally not actually seen one for sale forever.
If you have one or might know of one (or a project), I would love your help. My email is email@example.com