I'm still seeing them on Amazon.
If you're in a country that doesn't have Amazon let me know. I can order and ship to you.
I am a FIRM believer in compact phones and the more that people have these the stronger a signal we'll send to Sony. I will do everything in my power to make these phones sell.
I bought from Amazon, and yes I used the USA version.
As far as I'm aware you can flash the firmware and get the desired results regardless of model bought; the XDA thread linked has some comments from an international model user, you'd have to read that for more detail if you're wanting to go that route.
edit: this link has an affiliate code from camelcamelcamel.com in it. I don't work for them or get paid, just a user.
Same price on Amazon.
https://www.amazon.com/Sony-Xperia-XZ1-Compact-Unlocked/dp/B074P5FMGC/
Here's the Amazon US link: https://www.amazon.com/Sony-Xperia-XZ1-Compact-Unlocked/dp/B074P5FMGC
"Ships from and sold by Amazon.com."
bhPhotoVideo has it listed as Coming Soon.
Here is an Amazon.ca search & Amazon.com listing.
Amazon.com lists it with Band 66
, but it could be a copy/paste mistake.