OK, here's the situation:
My wife and I have both been commuting to work by bike for more than a decade. We both work on a college campus, an easy 1-mile ride from our house.
Now, we've got a baby. To carry her, we got a Douze cargo bike, which is absolutely fantastic. I can't recommend it enough. When our daughter is ready for it, we'll be able to drop her off at the campus daycare, right near our offices, without worrying about parking. That's huge.
However, we now realize that there will be many occasions when we'll need to switch bikes -- for instance, if I take the baby to school on the Douze, but my wife needs to take her home. I'm about 5'11'' and ride a 58cm bike; she's about 5'6" and rides about a 51cm. I can sort of ride her bike if I pull the seat way up, but she can't ride mine.
So what we need is probably a large-frame step-through bike with an easily adjustable seatpost. It's pretty flat where we live, so a 3-speed hub would be ideal. When we visited Copenhagen, we rode
cheap Danish bikes like these, which would be great, but I haven't seen anything like that in the USA. Any recommendations?