This feature is in our product roadmap however there is currently no timeline for implementation.
That said, If you are ready to get your hands on a bit of technical work, you can follow my blog post here: Use my own VPN Locations on InvizBox Go!
If you go for that option, have fun. The InvizBox Go is a nice piece of hardware to hack (if you go too far, there's always a way to flash the latest firmware from USB!)!