I remember as a kid learning chess from a book and there were lots of small chess games that utilised only a few of the pieces at a time.

for example Kn, B, R + 3 pawns Vs K,Q 3 pawns.

There might have also been a queen Vs all pawn game i played?

My son knows how all the pieces move but i think a full board is too much for him to fully concentrate on the options and potential threats.

Do any of you have any board game setups that might be fun for 10 year old kids to play?

no suggestions?

Just play with only king and pawns. 

Take a look at the few lessons/exercises in this set of material: http://www.chesskid.com/article/view/chesskidcoms-curriculum. It includes some excellent, simple exercises designed to teach/practice piece movements.

In the very near future, I would like to develop something that I have provisionally called "Semi-chess", with a few variations.  All variations are played by just folding a cardboard chessboard and playing on half the board.  Has anyone out there heard of such a game -- for children and for training purposes?  I played a first game a few days ago with my 8-year-old daughter.  It was her very first "chess" game ever and she could follow it pretty well.  The different variations could be extremely important for teaching beginners to play very well.