Mock-ups for a new website

Hi, we are making a New Online Based Program (PHP/MySQL) and we are looking to make Mock-ups for it. This system is a for back-end use only (Inventory control, Finical management and much more) - no shopping cart or blogging website - once awarded with the project we will provide you with all options & features that we will need. The main purpose of this mock-ups is so that we can play around and add features till we'll decide that its ready to go to production, therefor we will need some that is very easy to be reached so we can easily work together. Please only bid if you have solid previous experience and you are ready to work and finish this job and not be busy with other jobs. "Please note: Before being awarded with this job you will have to show us some samples of your previous work, so we can make sure you really experienced and not just training yourself on us!" Thanks