I am offering an entirely different spin. Since this is going to be a MySQL based jobsite, why reinvent the wheel? There is a wonderful software package called ForwardSQL which is essentially a suite of scripts written in C that I'm sure can do everything you need.
I would buy the package and pass the cost along to the client. Your time will be spent designing the site and NOT writing code.
The URL is dbwww.com. I have no affiliation with them, but offer this suggestion as I have used this software in the past and it is quality code.
You may need to write some custom apps depending on the nature of the project, but by and large the ForwardSQL program can handle 99% of your needs.
I have discovered that by using their code, my development time is quite rapid and has allowed me to win a number of project bids because of the decreased development time.
Just my