Wearable device is one of most hot topics this year in China(perhaps globally ), especially smart watch. Baidu Gudong bracelet, iWatch, Qihu360 kid guard bracelet, Coolpad watch,etc made by local vendors(OEM or ISP) either have been on sales or would be on sales soon.
There are still many challenges/barriers for smart watch currently such as power constraint, how to position, must-have features, HMI, etc. And selection of silicon solutions is one of big headache for those smart watch manufacturers. Actually there are lots of choices for ARM based silicon suitable for varied kinds of smart watch, from Cortex-M series MCU for "low" end to Cortex A series SoC for "mid/high" end.
Here I would like to list some of low power ARM based silicon good for smart watch for reference:
MediaTek MTK6515 single core Cortex-A9
MTK6572 dual core Cortex-A7
QCOM MSM8225 dual core Cortex-A5
Spreadtrum SC8810/SC7710 single core Cortex-A5
Rockchip RK2918 single core Cortex-A8
Allwinner A13 single core Cortex-A8
Allwinner A23 dual core Cortex-A7
Action ATM7021 dual core Cortex-A5
InfoTM iMAP x820 dual core Cortex-A5
Telechips TCC8923 dual core Cortex-A5
STMicroelectronics STM32F103, Cortex-M3, etc
Silicon Labs Precision 32 SiM3 U1xx, Cortex-M3
Texas Instruments Stellaris® 1000 serie Cortex-M3
NXP 17xx, Cortex-M3
Microchip SAM3 serie, Cortex-M3
The thread was originally created in November 2013. I am not sure Android Wear was widely available at the time.
Looking at the some of the SoCs, they support full blown Android, so I don't see why they couldn't run Android Wear. Of course not the microcontrollers based on ARM Cortex-M which don't have any MMUs, among other things.