Just buy Raspberry Pi 3 and you will have 64-bit ARM desktop hardware...
[1]: https://www.linux.com/news/raspberry-pi-3-still-essentially-...
> 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...
https://www.kraxel.org/blog/2016/04/fedora-on-raspberry-pi-u...