Found this awesome Family-Cycle in a story titled "Eccentric Cycles," which ran in the September 1949 issue of Mechanix Illustrated magazine. It was right under the French guy who strapped a 56-pound, four-tube radio to his bike so he could "listen to favorite programs."
It says that Roy S. Henrich of St. Louis simply welded "a small baby carriage" between two ordinary bikes, but to me, that thing looks like a torpedo casing, or at least a hanging car from a ride in a scary traveling carnival.
If you could figure out the steering, this thing could really have some potential. Or not, given the complete lack of mentions in the ensuing 60 years.
Eccentric Cycles, Mech. Ill, sept 49 [modernmechanix.com]
I doubt it steers with any grace, but it looks as if it works fine. There seem to be three static bars running across the front of the baby seat to hold it in place. It looks as if there's a fourth bar in front that runs from the yoke of one wheel to the yoke of another. That would allow in-sync steering, provided you and your partner didn't battle to wrestle control from each other every minute.
It can't be much wider than the quadricycles on east coach beaches and in resort areas. The mechanics seem to be similar; this particular example just looks slightly more primitive. Except for that cool kid-capsule.
Whoa - quadricycles have gotten way sleeker than the last time I looked. Check this out.