What's the point?
I'm mystified by this constant desire to consolidate all our devices into one all-encompassing hopeless compromise.
I own a big Dell laptop for work, a MacBook air for casual computing, a Nokia 105 for calls and text, a smartphone for those (rare) occasions when I need the internet on the move, and a Kindle for reading books. Each of these is better than any of the others for the thing I use it for (and I don't need a tablet because there's nothing they are good at).
Sure, it means I'm occasionally carrying 2 devices with me, but 90% of the time the only one I'm carrying weighs 70g and only needs to be charged once a fortnight.