Document management system with client able to access through 'my account' scenario

I want to provide clients with a 'my account' facility so that they can log in with user name and password to see what stage their job is at....I suppose it could be like a document management system.
There are two types of job each with a number of stages and options at various stages.
At each stage these options may include printing documents off without the client being able to alter them,making a payment to us etc.
We need to send chaser emails and letters (mailmerge) if tasks arent completed by the client or a third party by the required time scale.
Web based using php and mysql.
This project would suit someone who can work fexibly as I am sure aspects will come up as the project progresses .....we are likely to think of of more functionality and you will say what about doing this and that .......