Dashboard Customization

Hi All,

I am using wordpress as a CMS for clients. Firstly I wanted to know how far I can go with regards to the dashboard. Does wordpress require link backs and their logo in the Dashboard. I want to be able to completely customize the admin section from client to client. I know this requires diving deep into the php code and editing the core functions. Is this allowed. Also is there any information out there that explains the code and how to edit it? For example if I am building a site for a realtor, instead of add post I would want it to be add house. That is just an example?

Thank you and your help will be much appreciated.

~Ty