Just added a new set to my collection of free paper kit buildings. This one is "Pretty City" and it includes shops, multi-family dwellings and warehouses. There are no instructions with this file, so you will have to get them from one of my other paper kit sets. I have added the Pretty City set to the page of paper building kits. They can be scaled easily from N to O. The trick is to use the door as your guide.
http://www.thortrains.net/freecoms.html
Size buildings until the doors are these heights:
N: 13 to 15mm
TT - 6.5 to 7 tenths of an inch
HO - 22 - 24mm
S and 3/16" O27 - 1 3/16 to 1 5/16 inches
O - 1 5/8 to 1 3/4
BTW - I have another set of buildings that are right for scales S to O here. They have a small footprint, allowing more homes in less space.:
http://www.thortrains.net/download25.html
Happy New Year!