Which touchscreen device is really usable with one hand?
certainly not any one with a larger 4 inch display (try to reach the upper left corner of the screen with your right thumb - it's not something you even try getting used to).
And you did say *fully* usable with one hand, right?
I see that working only as long as neither typing nor browsing is involved. pinch-to-zoom with just one hand? please show me! How many people do you ever see typing with one hand (i.e. the same hand they are holding the device with)?
Be honest: If your messages are longer than one phrase, you usually bother to employ the second hand as well, or postpone the typing to a situation where you have both hands available: true or false?
To me, completely one-handed usage of phones died with touchscreens (maybe due to the fact that my first touchscreen device was a N900 - but my next one, C7, is in no way better suited)...