When I built mu first tallbike about ten years back, I had a few guys older then me stop me and say they used to make them by flipping their bikes upside down and welding pipes on them, like in the picture here. They claimed the 70s though. This obviously predates that. I think this pic was posted in the thread discussing butterfly bars. Seems to be the exaggeration of the long (cycle truck style) stem and butterfly bar trend of the late 50s.
That long stem "engineering" looks crazy dangerous! (But more danger equals more fun!) I like that the dude in the right has a fore brake, but not hooked up yet, and they are in front of a welding/blacksmith shop. Looks like fairly fresh welding on the frames. Maybe this was their test ride!
Looks Southern Cal style to me,they always set standards back in the day,Early to mid sixties,,they were on there way to the local hardware store to get a cable long enough for the front fore arm brake
If you grew up in the 50's and 60's you would have seen these. My friend built one, mid 60's, and it was fun to ride but extra "skill-effort" was needed to mount and dismount. And we didn't wear helmets!