Custom Drupal installation with secured node access

We need a simple Drupal 6 installation to provide a restricted download section to our customers. Once they buy a product, they can download updates for one year AND for a full version cycle (this means that ordering version 1.1 will give access to each version update till version 2.1 included), and we need a very simple web-site to enforce those rules. The Drupal installation must meet the following rules: 1) Users have the following hidden (except for admin) profile fields: a) List of products ordered by that user (example: product1, product2, product3...) b) Date of the order for each product (example: product1 ordered 21/08/09) c) Version of the specific product when ordered (example: product1 ordered at version 2.1.0.2) 2) Nodes are created with each new release and have the following fields: a) Associated product name (example: product1, product2...) b) Release product version (example: 2.1.0.2) c) Release date (example: 21/08/09) d) Private download link to a ZIP or EXE file for that release: The link must not work if the user send it to someone else without the correct rights 3) Those nodes access will be granted per-user based on the following rules: a) Logged-in user ordered the product associated with the node b) AND (The version of the node has not reached a full cycle c) OR The product date is less than a year from the ordering date) Examples of access with a user who ordered "product3" on the "21/08/2009" whose version was "1.3.5.4": 1) User CAN'T access any node of "product1", "product2" and any other product which is not "product3" 2) User CAN'T access a node with a version 2.3.6.0 whose date is the 22/08/2010: both a full version cycle has been reached and a full year too 3) User CAN access a node with a version 2.3.6.0 whose date is the 20/08/2010: a full year hasn't been reached and the download is still valid 4) User CAN access a node with a version 2.1.0.4 whose date is the 22/08/2010: a full version cycle hasn't been reached and the download is still valid Regarding the projects exigences: - Products versions MUST follow the rule "major.minor.release.build" so for example "2.1.0.2" is a correct version number; - Project MUST use Drupal 6 (Drupal 5 or older is not an option, neither are any other CMS); - Project MAY use either existing Drupal functionalities, public or custom modules. We don't care as long as the public module is still maintained and at least in release candidate state; - No access will be given to our servers. You will just provide the Drupal folder and associated database and we will proceed with the installation; - We DO NOT need any custom theme for this installation. The default Drupal theme is good for us; - Payment will be made once the project has been fully tested by us. If this is not OK with you, please don't bid. Happy bidding :)