for 240mm 4x5 portraits, I use a Cambo Maxiportrait, which uses a 240mm lens. I fitted it with the rangefinder from a Polaroid bigshot. It works great, perfect for head-shots, easily handheld. It's a bit of a one-purpose camera, but it is excellent for that purpose.
You could probably fit the Nikkor 240 to it, though it would take a bit of modification. The stock lenses it came with are the 240/6.3 Congo (Commercial Ektar clone), or the 240/9 G-Claron.
I can post pics if need be but they are easily found online too.