Neither the iPad Mini nor the iPad fully function as a mobile phone. You haven't offered an alternative, you've completely ignored a key factor and still not accounted for calligraphy.
The iPhone 5 has a 4" screen, but with weird dimensions of 640x1136. That's pretty narrow, though I'll readily admit I used to read on my iPod Touch with a very small font. Still, I find it an odd design move.
I currently have the Google Galaxy Nexus at 4.65" with the movie friendly 720x1280 that's wider in portrait mode, the way most people would read on a mobile phone. It's not an unwieldy pocket-choking phone, especially when not in a third party protective case.
The S4 at 5" with a true-to-pixel HD 1080x1920 comes next in size. Having played with one, I find it still doesn't feel to unwieldy at only .35" bigger than my Nexus.
Finally for that next step up - and note it is a fully functional mobile phone and not a tablet with Skype to make it a "phone" - is the Samsung Note II. This time with a resistive screen that is better suited for use with a stylus - which comes with it's own spring-loaded dock within the casing of the phone. Now, that does feel big. Kinda like those big wide men's wallets that are meant for big trenchcoat pockets or a briefcase. Also dangerously close to that Nokia N-Gage "side-talking" feeling when used as a phone. No argument there, it's on the big side. But you know what? Those bluetooth earpieces are all over Singapore and I imagine China and Taiwan are no different.