Tarnicus: With the recent changes to regional trading on Steam, Brazil (Nuuvem) is out, depending on the game.
Nuuvem's ontop of it, in the games description it now says under the DRM section if it's region locked. Also, the Enhanced Steam add-on tells you if a game is region locked, and as a last resort there's SteamDB.
Tarnicus: The Spellforce link is for Steam :) Amazon don't want to accept my Australian credit and debit cards anymore :( Ah well I had fun using McDonalds in the USA as my address for a couple of years to get some great deals from them.
lol, my address there still works.
Can use Borderlinx for a legit address, a free service which only charges if you ship a parcel through them. I had no issues with the Spellforce using my Northern Territory CC, though for some games (e.g. Beyond Earth) Amazon will ping your bank to check it's location. To bypass that you can use Amex (it doesn't care where it's registered) or purchase US Amazon gift cards fro places like UK.
I just bought region locked Metro Last Redux from Amazon today, redeems on Steam as (NA) North American version but still installs, downloads, and plays. Spent an hour playing just to make sure. Had to test it out as Enhanced Steam said it wasn't region locked.
Edit: Also, on the Borderlands link you provided there is a spot where Amazon puts the region lock message "Requires Steam Client to activate. Steam key only valid in North America", just below the "Download time".
2nd Edit: It let me buy another SpellForce Complete without issue ...... :/