Here is a United Trifold folding bike, which is a weird blend of Dahon and Brompton frame designs. The top half of the bike (seat post, handlepost) is based on Dahon standards, while the bottom half is referenced from Brompton, although not completely.
The main frame folds opposite to Brompton's direction, while the rear triangle has a OLD of 135 mm to fit Shimano internal hubs.
I modified this bike to simplify it, by making it a single speed bike for casual rides. At the same time, the bike weight can be reduced greatly since the internal hub system has been replaced by a simple single speed drivetrain.
Later on, I experimented with installing an 11 speed derailleur drivetrain, just to try and see if it was possible.
Check out the posts below for all the details!