San Francisco-based designer Todd Hamilton has mocked-up what could be one of the best iWatch concepts to date. Unlike a few others, Hamilton ditched the old-school watch look and went for a FuelBand-like design. Given its Apple roots, user interface components of iOS 7 were incorporated as well - making for a stylish build.We've seen a FuelBand-like concept before, but the screen's orientation was horizontal and would be uncomfortable to use on the wrist. Hamilton said it needs to feel natural on the wrist by being vertical, and his mock-up includes swiping gestures: tap to use Siri, swipe up to unlock, and pull down to view notifications. A single button on the left acts as the home button, and two more on the other side control the volume.Like the iPhone and iPad, there is a springboard to access apps. There are four app icons vertically stacked with a page controller on the right. Swiping up or down takes you between your pages of apps, and pressing the home button takes you back to the lock screen once you're done swiping around.Also depicted are a fitness app for tracking running time, calories burned and distance. The iWatch is believed to connect to an iPhone over Bluetooth to tether data, so Hamilton has also included the ability to call and manage contacts directly from the iWatch.Apple and Nike have been getting cosy over the last year, so it certainly wouldn't surprise us if a bit of influence wasn't taken for the iWatch. At this point Apple continues to remain quiet on specifics, so we're just left to speculate - which can be fun.Previous rumours have said the Cupertino company has been testing different sizes of OLED displays. It was thought this was to find out the perfect size through testing on prototypes, but a November report from the Korea Herald said both 1.3-inch and 1.7-inch OLED panels were to be utilised to offer different size choices.Speaking on a year-end conference call with investors in 2013, Apple CEO Tim Cook hinted at new product categories during 2014. Industry analysts and pundits have long pegged the smartwatch, or possibly a television, as the device to be released. It's not clear if manufacturing issues have pushed the launch beyond this year.