In fact, the final release's ISOs were available on Heatnet servers for some hours (http://ftp.heanet.ie/pub/linuxmint.com/stable/12/) but there was no oficial announcement. I guess the real deal will come pretty soon.

Some of the mirrors had it , then (pulled it?).

Here's a US mirror that has the Final isos now: http://mirror.yellowfiber.net/linuxmint/stable/12/

For the rest of the countries, try tweaking the URLs similar to the above and you may get lucky.