I just bought an iPhone 5, and was planning on listing my (what I thought, was) 5th generation iPod touch I bought last year, but Glyde and Apple support both claim there are only 32GB and 64GB 5th generation iPod touches, where as, mine is only 8GB.
My girlfriend has the iPhone 4S, and my iPod's screen is bigger than hers, which leads me to believe it is an iPod touch 5th Gen, but I can't find any documentation on it existing in the wild. It also has no rear camera, only a front facing one.
The model number laser etched on the back is: A1421
Best Answer
You do have a 5th Generation iPod touch, and it's the 16GB model.
If you check out Apple's website for current-generation iPod touches, specifically the "tech specs" page, you'll see that there are two types available today. The left one (the one with no metal circle on the bottom-left of the back) is the one you have.
On your Usage page, you have two numbers: available and used. The confusion is probably because "available" here means how much space you have left for new content, not the total amount available to you. If you add the two numbers together, you'll have roughly ~13GB of total storage. (the remaining storage being taken up by the OS)
Also, Apple has an article on identifying your iPod that can often help find the marketing name for any iPod that's been released.