lol, I can see an entire ad campaign about which device to take on heavy days vs light days, and why you need one of each. Seriosly though, the difference between a big iPod and a small iPad would be if the device runs iPad specific apps or iPod only.
There will not be a iPod Mini and a iPod Touch. I suspect that someone took a iPad image, photoshopped it to make it smaller. Apple ha a limited number of SKU's and iPad Mini is not one of them.
It will be iPod Classic, iPod Shuffle, iPod Touch, iPad, iPod Nano