Using resistor networks as voltage ladder
There are typically two arrangements: 
Resistor networks wired together with one common point.


Or these kinds:



If you need a ladder, you can buy a network and connect the terminals. Why aren't there more configurations? Because manufacturers don't want to exclude customers options with a more specific configuration. 



Image source 

There are also precision networks that have better tolerances and resistor matches in one IC



The only other place where I think you'd see custom resistor ladders is in the high voltage sector where spacing is important to prevent arcing.