An e-commerce website in Magento

Hello, I need an e-commerce site, (I think a good solution could be in Magento) with the following requirements: 1. Login 2. Order 3. Search 4. Item details 5. Stock 6. Checkout 7. Payment 8. Credit check 9. Order status 10. Shipping 11. Confirmation 12. The system should support sending e-mail and SMS. 13. Pricing (by the admin) by percentage of category, manufacture and/or item. 14. Multi-Users (Some users will be allowed to buy just with an invoice and some users will be required to pay on-line) At present the client's site work against one supplier with a web service provided by the supplier. For example when pressing manufactures my client's site(s) send a query to the web service and the response is shown on the GUI interface of my client's site. Therefore, your work as well should be able to import files, from different suppliers, like items, price, and other basic information. Worth mentioning that some of the suppliers does not support a web service, so the files will be imported on a daily basis. Most of my client's products will have the same code even when buying the same item from different suppliers. So the pricing should be based on lowest price in catalog and the correspondent Order should be sent to the right supplier (the one with the lowest price). Here is a link to the suppliers webservice: [login to view URL] Here it is more or less an example of a site that works like the one my client is requiring: [login to view URL] I'll need from you a detailed proposal for the building and implementation of this site. Please include as well: - Time of development and of the implementation - Cost and terms of payment - The cost of supporting the site once it will be ready, - The cost of changes and/or additions Please clearly state what information or data you're required to begin the project. Thank you very much Abraham