Custom Wordpress plugin: Reddit Gold-like donations

I'm in need of a developer to create a Reddit Gold like plugin for Wordpress. You can see Reddit Gold in action on [login to view URL] in the sidebar there. The idea is to replicate the functionality and make it available as a Wordpress plugin. Requirements: 1. Integration with two payment processing services, PayPal and Amazon Payments 2. Options to hide elements on the blog for members who have made a donation using PHP enclosures, and preferably also automation. 3. Security hardening 4. Compatibility with the most recent version of Wordpress. 5. That you are available to upgrade the plugin rapidly (paid) if it breaks due to Wordpress updates or changes in payment processing. I have created a project plan and attached it as a file. Make sure you read through it as it includes all the relevant bits of information that help you make a proper bid on the project. If you bid on the project, make sure to include the time that you need to create the project. Since I want to sell the plugin to other webmasters, I'd like to hear your thoughts on adding security measures to the plugin to prevent (easy) copying and unauthorized uses of it.