Amazon is expanding its portfolio of products as it looks to tackle the mobile market head on. The online retailer is said currently to be working on five or six tablet SKUs (stock-keeping units) of different sizes. However, rather than screen sizes, some or all of them may just end up offering different storage capacities.

Reuters writes that the Amazon devices will vary in screen size, with a 10-inch model tablet suggested, after relevant claims from Demos Parneros, president of US Retail for Staples, which ships the Amazon Kindle Fire.

So far though, Amazon has refused to comment. 

An Amazon Kindle Fire 2 is expected to debut in the coming months, with some speculation that it will house a screen that will rival the size of the iPad. But could this be the 10-inch model Parneros is talking about rather than a rival device to the much-rumoured iPad mini?

Although the SKUs could be multiple versions of the same device, some are guessing that, with five or six of them being stockpiled, we could we be seeing a Fire 3, 4 and 5 in the near future? It could even be that one of these SKUs could, in fact, be an Amazon smartphone?

Now that really would be an expansion of Amazon's presence in the mobile market.

What do you want to see from Amazon in terms of the mobile platform? Let us know in the comments below...