Greetings!!
From your post we understand that you need eBay API database s/w that allows bulk upload & download, via csv file with a GUI. The following are the functions to be done:
CSV Functions:
1) Import CSV file into program with product details
2) From imported csv, create products with a set of fields in backend panel.
3) All the products can be viewed, edited, changed before being uploaded to front end eBay
4) Upload newly made listings from CSV and create each individual listing to eBay.
5) Export all current live listings into a backup CSV file, along with current online images copied to a local folder.
Database functions:
1) Create products in database backend with a editable fields of information
2) Organise products into tags such as Categories, Brands etc to easily identify one product from thousands.
3) Create product listings directly from database
4) Download all current online listings from database & update them live
5) View all current listings in backend
6) Edit the listings through backend & update live on eBay store.
Requirements needed:
1) Windows 7 or higher compatible
2) Good looking nice graphical interface
3) Software will be updated & maintained
4) Option to update new API's for Magento and other retail channels.
So with our skills sets such as PHP, CodeIgniter, HTML, eBay, MySQL, Javascript, Jquery you can rely on us for quality service.
Hope you are comfortable with our proposal & looking for early response.
Warm Regards
Suraj