Reports are surfacing, in The Wall Street Journal (subscription required, free trial available to Fools) and elsewhere, that AMZN) will soon be expanding into another profitable line of business: apparel.

According to the Journal, "In its most significant effort to expand its product line in a year, the Internet retailer is developing an online apparel store in partnership with major clothing retailers, and will introduce the store in time for the holiday shopping season." The retailers in question include the Gap(NYSE: GPS), Sears, Roebuck's(NYSE: S) Land's End unit, and Nordstrom(NYSE: JWN).

This seems to be a promising win-win arrangement. Amazon will offer its millions of shoppers the chance to purchase clothing (and footwear) from the catalogs of major apparel retailers. The clothing retailers will maintain the inventory (thus sparing Amazon much overhead and money) and process orders. Combining the effective Amazon online shopping environment and tools with the deep product lines of major old-guard retailers sure sounds like a smart idea. Amazon has actually already been forming similar partnerships with Toys "R" Us(NYSE: TOY), Circuit City(NYSE: CC), Office Depot(NYSE: ODP), and Target(NYSE: TGT).

The Journal notes that clothing is one of the top online sales categories, expected to generate $5.2 billion in sales this year, 18% more than last year. It also points out that, "In the third quarter, 23% of the goods Amazon sold in North America were through transactions with third parties, including brand-name merchants and individual sellers of used goods." As this part of its business grows, Amazon becomes more like eBay(Nasdaq: EBAY), whose inventory-free business model has been considered superior to that of the more warehouse-intensive Amazon.

Considering that several of these new partners have been struggling of late (think Gap and Sears), this new deal could help boost their bottom lines. Is there any way Kmart(NYSE: KM) can sneak itself in there?

Selena Maranjian owns shares of Amazon. For more about her, view her profile. You might also be interested in books she has written or co-written: The Motley Fool Money Guide and The Motley Fool Investment Guide for Teens . The Motley Fool is Fools writing for Fools.