Update:

>> in terms of 64-bit ARMv8 (AArch64) cores, there is announced so far:
>> - Cortex-A53 and Cortex-A57 from ARM Ltd.
>> - Denver from nVidia
>> - X-Gene from Applied Micro
>> - Thunder from Cavium
>> - Cyclone from Apple

> - Vulcan from Broadcom
> - K12 from AMD

More details on Cavium's ThunderX:

http://www.cavium.com/newsevents_Cavium_Introduces_ThunderX_A_2.5_GHz_48_Core_Family_of_Workload_Optimized_Processors_for_Next_Generation_Data_Center_and_Cloud_Applications.html
http://www.cavium.com/ThunderX_ARM_Processors.html