15 and 17 inch Ultrabooks?

15 and 17 inch laptops are mobile offices. Not Ultrabooks. You might know that the Apple MacBook Air only comes in an 11 inch form, and 13 inch. This is smart because past 13 inches, the device becomes bigger, and defeats the purpose of being thin. Of course, it wouldn't be called an Ultrabook if it wasn't thin, but the entire point is for your computer to be portable, and 13 and 11 inches are extremely portable. I think that 15 and 17 inch laptops will be underpowered for their form factor. Either way, let's get to the news; Samsung's Series 9 laptops will come in 15 and 17 inches, but as my little rant stated, they aren't practical. For me, at least.