George Duke wrote on Thu, Feb 25, 2010 08:33 PM UTC:
Russian Fortress has four by fours (4x4) like Gala:
http://www.chessvariants.org/historic.dir/gala.html.
Recall that Flowerman recently has four by sixes (4x6):
http://www.chessvariants.org/index/displaycomment.php?commentid=24998.
Sub-boards are another great avenue toward proliferation. Reasonable sub-boards might vary from 1x1 to 7x7 for (49-7), 42 possibilities. Or even be odd-shaped like Ramayana:
http://www.chessvariants.org/large.dir/contest84/ramayanachess.html.