Samsung's Gear S is a Tizen-based smartwatch that includes a 3G modem, so it does not need to pair with a smartphone to place calls or send or receive messages (although of course it can do so via Bluetooth or Wi-Fi). It has a 2" 360x480 (300 PPI) plastic-based flexible/curved Super AMOLED display. Other features include a 1 Ghz CPU, GPS, heart-rate and motion sensors and a 300 mAh battery that should last for two days.
The Gear S is available on Amazon for around $400.
2" curved 360x480 Super AMOLED