How to modularise an application in Joomla

[te...@irataweb.com.au]

Hi,

I am looking for ideas or approaches in which I could modularise a business application as a Joomla extension.

The 'common' way I have found in examples so far of seem to break the application down to smaller functional components as separate components, i.e.
com_customers
com_accounts
com_emails
com_functionA
com_functionB

I have to many real issues with this approach and unless something else comes up, that is looking like the way I am going to go.

An alternative theoretical approach can be seen in this sildeshare,
https://www.slideshare.net/joomila/joomla-development-presentation/21-Understand_Modular_component_Module_file

The above slideshare, if it works has some merits too for what I want to do however it led me to ask this question to see if there any other approaches out there for organising an application where I can reuse the same code amongst clients, avoid a huge monolithic code base per client to duplicate and maintain and general just make my project(s) more manageable. 

A simple example maybe to have two clients where they share some common code and their own without the need to maintain two complete separate environments one for each client.

Client1
_customers
_accounts
_invoicing
_functionA

Client2
_customers
_emails
_invoicing
_functionB


If anyone can suggest some further reading or examples of extensions that have already do this I would be interested to receive their comments.

Regards,
Terry