I found this one on Craigslist and picked it up today...
http://www.myoldtools.com/boxjoint/box5.jpg
http://www.myoldtools.com/boxjoint/box4.jpg
Superior Machine Works Chicago purpose made box joint machine. It appears complete. It was converted from babbit to ball bearings, but the original babbit boxes and caps were saved.
http://www.myoldtools.com/boxjoint/box2.jpg
It doesn't appear that the shaft was permanently modified either. It has handwheels with double gears driving double screws to set depth and clamp boards to the carriage.
http://www.myoldtools.com/boxjoint/box7.jpg
The orginal carriage handle is missing. I'm guessing it might have been a ships wheel, but maybe not. It came with a big Western Electric motor, belt drive. It came with a box of extra cutters and spacers. The ones in it are carbide tipped.
http://www.myoldtools.com/boxjoint/box3.jpg

I thought the beekeeping community might like to see what was used historically to produce wooden ware. I imagine the current machines aren't a lot different, just more automated and with better guards. I collect old woodworking machinery as a hobby.