Custom PHP Sales/Reseller/Affiliate

I am in need of a very site specific software suite. I sell web software, installation of the software, and web hosting. I want to allow people to resell just the software but they must pre-purchase the licenses first. I also want to allow affiliates to advertise the software and receive a fixed amount for each sale. I need to be able to manage all aspects of it. Resellers will log in to their account, be able to buy more licenses, assign license numbers to end users, and edit their information. Clients will log in to their account and be able to view the products and services they have purchased and download any files they have purchased, view their license information, and renew their license if applicable. The software needs to be written in PHP and use MySQL. It also needs to be neatly coded so if any modifications are needed we can do them at a later date, it must be easy to follow. The software, once paid for, will become the property of The T2 Web Group. I do not need fancy pages, I just want to be able to define a header and footer, then the other output should be black text on a white background. This needs to look like the rest of the site it's going into. The software will need to access a vBulletin database. You can either just create blank functions and then make calls to those functions, and I'll put the vBulletin code in the functions or you can write the functions into the code. This function is just so the client can access the protected areas of a support forum and check if logged in, nothing more. I want an all-in-one cookie, the user's forum, reseller, affiliate and client log in should all be the same, I don't want separate log ins. Ex. : If they are logged in to the forum they should be logged into the client area as well. In the descriptions below, if it says "database" that means it's a database for this new software, if it says "vBulletin database" that means it's the vBulletin database. There is a complete list found at [login to view URL]