I think the Nagaoka isn't terribly different from other Japanese wooden folding view cameras like Tachihara and the Ikeda Anba (which is particularly light weight). What was attractive about it as compared with other cameras?
I just googled 'nagaoka seisakusho' and found numerous citations. It's a darn nice looking camera from the pic I found on one of the sites. There's enough there for you to google it as well and read from the available sites as there were too many for it to seem worthwhile for me to choose just one.
The Nagaoka cameras are pretty much identical to the Anba Ikeda camera, the only difference being that Anba cameras have red bellows, while the Nagaoka's are black. Both the Nagaoka and the Anba are very compact and lightweight (less than 3 lbs), but are not very rigid. The Tachihara and the Wista cameras are a bit heavier, but are much more solid, and have better movements.
I had one for a few years, combined with a small tripod, 150mm G-Claron, and two graphmatics it made a very lightweight travel kit which easily fit into a small backpack. On the other hand, I often found the limitations of the camera (12" bellows, limited rise/fall, very limited swing) infuriating.
These tend to sell for about $400 on eBay, which is probably the best place to locate one.