Best Practices for Customization

[agaluski]

Are there any articles or threads on the best method for customizing WebERP, such as forms and or small bug fixes until a new version that contains the fix is installed? What I am envisioning is something with a separate path is read before the weberp core and if the same file is found in /custom/ then it is used otherwise the core code is used. I'm a newbie so if this exists please point me to any associated reading materials.
I see a ton of great stuff in this package but need some additional small things (mostly around outputs) that would make this usable in our business

Andrew