Author is asking for 64-bit ARM hardware, not software...
> The raspberry pi 3 runs in 32 and 64 mode. There is no >>LINUX<< 64-bit kernel for it currently...
To my knowledge, rpi3 has 64-bit CPU, but all operating systems and bootloaders available run only in 32-bit mode, no exceptions. That means that rpi3 in future theoretically can run in 64-bit mode, but certainly does not today.
So you know even all non-public bootloaders and OS-es...