I'll just drop by to plug my Brazil feature...
http://www.coh2.org/news/30318/forgotten-nations-brazil
Hungary/Romania/Finland are all individually as variant Ostheer if you tweak a few things to do them justice.
Once you get to the minor minors like Slovakia and Croatia there isn't much to do to make them unique though,
France you can add as a whole faction competitive in 1944-45 meta if you make some assumptions about the likely developments had they not been taken out in 1940
At the moment Poland would strain even my creativity to get useful however
