Create an eBook signing service - repost

I need a web service that facilitates authors of eBooks to have their eBooks (in ePub format) signed and delivered to their customers. PLEASE READ CAREFULLY BEFORE BIDDING: THIS IS NOT ABOUT BUILDING AN EBOOK STORE OR A SIMPLE WEBSITE. This is the usage scenario that the service must cover: - Author logs into service - Author uploads the eBook (in ePub or Mobipocket format) or enters a publicly available link to it (file size 15 MB max.) - Author confirms having the respective intellectual property rights - Author enters keywords in the eBook that should be adapted with the corresponding values - Author enters email address of customer - eBook gets converted - converted eBook gets sent to the customer - input of the author and original eBook might be saved on the server if the author wishes I added a simple sketch of the "core" interface. Details about the conversion process: ePub eBooks (and Mobipocket files) are XHTML files in a ZIP container with an .ePub file association. The eBooks to be signed will contain some key fields that are defined by keywords. Please see the doc file for details. The conversion process looks for all the keys in the original ePub and changes them to the content the author has given. The result is saved in a copy of the eBook file to be sent to the customer. If no content is given for a key, the author gets a warning. Also, there is a warning if a key doesn't exist in the file the author has given content for. The result is an ebook where all the keys are exchanged by the content the author has given into the service. Ideally, the service should fit into a wordpress blog. Later, the service might be expanded. PHP would be fine. MySQL is available. Please quote "ebook signing" in your application so I can see you have actually read the description. Thanks a lot! Any questions?