Is it possible for the height of the machine to be increased to make things that are taller?
Yup.
https://www.v1engineering.com/assembly/machine-size/
https://www.v1engineering.com/assembly/conduit-rails-tubes-pipes/
It depends on what you plan to do. There is no theoretical limit, but there are some practical limits, for instance if you plan on milling, having a tall Z axis will make things much harder.
You should first explain your plan if you want useful advice.