Originally Posted by Amesja

Longer seat post on the biggest frame size you can find. By the time you add a Brooks you add an extra inch or more with the springs anyhow. With a step-through what does it matter if you have a really long seatpost? Almost all the old Raleigh/English 3-speeds have a 25.4mm seatpost which is the same as many/most older BMX bikes if I recall. You can buy them CHEAP on Amazon. They made a lot of good strong long-ash seatposts for BMX bikes. Some even have a curve to them so you can get back further from the bars if that is what you want.