Ataxx, Aquataxx have a board of 7x7.

http://www.chessvariants.com/index/sameboard.php?itemid=LetterChess
lists about 15 games with a 7x7 board.

And finally,
There are many forms of Tafl, with boards measuring from grids of 7-by-7 (with 49 squares) up to 19-by-19 (with 361), though the mean is a grid of 9-by-9, with 81 squares. As the grid of squares is odd-numbered, there is a central square, which is called the Konakis or Nowl, and represents both the Pole Star, and the navel of the earth. The Lappish form of Tafl was called Tablut, and because of the nomadic life, was played using a cloth-board, with embroidered squares, while the English version (Tawlbort) was played using boards made of wood, metal, whale-bone, or walrus-ivory; the use of bone and ivory was significant in that it symbolised the wyrd and death ipplicit in the board game.

Aint this little web library a great thing??

Rick