Is it possible?
In short: No.
Long version: MWS is an API to work with your own merchant data on Amazon. You cannot see information that originates from other merchants. You can't see their stocked quantities, you can't see their prices etc.
Other APIs such as the Product Advertising API do something entirely different. They let you access the stuff Amazon shows on its webpage, pretty much the same as a browser would, only in XML form. To some degree this information will be data originating from yourself, other data will come from other sellers. You can do an ItemLookup
and see who (else) is selling a product, and at which price. You can specify which response groups (parts of the available data) you are interested in. However, none of those include TotalNew
attribute per merchant. So unless you know the stocked quantities of every merchant but one specific seller, you can't tell who is stocking which quantity. I know the website shows if a seller's stock is below 20 items - I don't think any API does the same.