Great news, piece fans!
The entire set of pieces are be available as an extra or stand alone item on the WG site:
Not to throw a wet towel on this one.
But, you might want to find out the tables of equipment on this before you buy the stand alone pieces and think you are getting full usable armies. Are they full sets of each country as defined by the game (e.g., very small unit counts of Italians, Chinese, & French), or more robust sets of each nation like Germany, Japan, US, & U.k.
I'd like to have a full set of each color, but it doesn't arrive out of the box that way.
I was a little disappointed by some of the piece counts (e.g., jets). You only get 1, so it becomes difficult to deploy in multiple theaters of war.