I found this blog posting today, relevant I think
"However searching for “TW64 nRF51822” does find some watches marketed as a TW64 which do contain the nRF51822, which lead me to Shenzhen DO Intelligent Technology Co., Ltd. on Alibaba. I contacted them to find out more details and found that all of their smart watch/ fitness trackers use the nRF51822
Their product numbers are P101,P102,ID100HR,ID105,ID105HR,ID107,ID107HR,ID101HR,ID110HR,ID111HR and ID115HR
So if you are looking for an nRF51 based smart watch, your best bet is to search using one of those model numbers, and double check the details in the eBay / AliExpress / Gearbest etc listing to confirm it does mention the nRF51822
In the end I decided to buy an ID100HR and a ID107HR, via AliExpress."
These caveats, I assume, guarantee getting a fitness band with a nRF51822 ARM BLE SoC on board...