I FOUND ONE!
I bought this 1986 beauty at the Cambridge Antique Market today. The man who runs the bike department was super-duper helpful, considering that I don't know the first think about bikes (let's put it this way: I asked how exactly to put a lock on a bike). This one is super simple and easy to ride, I think it was made by Sears in the 80s when they still manufactured bikes. Regardless, I rode it home with only one minor injury (I tried to carry it up the stairs to my apartment and there was a finger-pinching incident) and only slight embarrassment involving a bridge and some roller-bladers. It will take some getting used to, but as you can see in the picture above, it's the perfect season for outdoor experimentation!