OK, this is just pure guessing, BUT...
Before last announcement we had 15 bands left, and surprisingly the suitcase has 15 flags. Six of these flags belonged to bands from the announcement itself: ANVIL from Canada, THE HATE COLONY from Norway, GAMA BOMB from Ireland, SUBORNED from Switzerland, CLAIM THE THRONE from Australia and MONSTROSITY from USA. That leaves 9 flags left and 9 bands still to be announced. So yeah, I'm guessing we'll get one band from each of these flags, being my guess - with a lot of wishful thinking:
Sweden - At The Gates (heavily rumored)
England - Sylosis (some rumors)
Denmark - Mercenary (please??)
Israel - Amaseffer or Arafel (pure guess)
Colombia - Nova Orbis (not a single clue so random guess)
Belgium - Aborted (random guess)
Finland - Sonata Arctica (heavily rumored)
Poland - Pathfinder (please??)
Germany - Gamma Ray (rumored)
Let's see if I got any of these right.