Auction Listing Management Tool/ Database

We currently sell on eBay and on our website. We want to create a product inventory database (preferably online) similar to trackvia or caspio. The type of database you used to build from does not matter, mysql, ms access, ms sql, dabbledb, caspio, etc. While there are tons of online database, I will primarily use this database to create multiple variations of product titles for my various sales channels. I already have my own inventory database. I just need a separate database to do few things besides storing data: 1) Allow multiple users (up to 10 users) to simultaneously enter data 2) Product attributes are broken into the tiniest bit of information and enter into the database. I want the database to automatically concatenate(string) together values from different fields and output in a separate field. Take for example data such as "red, blackberry, 8300, charger" I want the database to automatically create a filter/query/view that will display alternate auction product titles for example, Red Blackberry 8300 Charger, Red Charger for Blackberry 8300, Blackberry 8300 Red Charger. These alternate products titles are automatically created in a query whenever the inventory table fields are populated, and I would be able to export this out and uploaded to my corresponding sales channels. 3) A script to test for broken url images, to see if the image does exists or not. I host my image for example [login to view URL] I want the script to automatically filter out the products with bad image urls 4) I want to be able to automatically filter auctions titles that have more than 55 characters 5) Search and filter out duplicates 6) Be able to designate my own primary key, for ease on importing/exporting and updating large number of records (up to 30,000 records) Note: I am able to do all the following above with MS Access currently, but I prefer something more robust that will allow up to 10 people access at the same time and simultaneously enter, export, import data and not have to worry about backup, and saving/transfering files on a desktop This database can be stored in a third-party hosting company or own my own server necessary.