All you have to do is take the phpbb template/style I will provide you, and simply replace the header at the top with a predesigned header which I will provide you. I will also provide you with a jpg image which was made for me showing you how it should look.
I will provide you with the template and the replacement header, all you have to do insert the image into the style/template and code it so that it fits and looks as it should. A fairly simple job. Please let me know if you can do this, and if possible please provide me with any examples of work you may have done similar. Thank you.
Here is a link to a demo of the template you will be changing. Essentially you will be removing the titanium portion at the top and replacing it with an image that i will provide to the winning bidder.