hi kite-kid
for my GCSE project my problem use to use the wind to do something. basical a kite board has been done and it is not a new idea, so unless you can get a radically new idea you will not get as gooder mark.
i had the idea of a kite board but i did not do it because instead i make a land yacht. oh yer, the seat broke and the mast did not fit in the mast step.
one of my friend made a mountain board, with a new idea. it had 1 big wheel at the back and small wheel at the front. the problem he had was with the steering. it did not work well at low speed because it was not a 'leaning' board. instead he push or pulled the back wheel around.
i do not no what your problem is. but a little tip is not to say your problem is to design and make a kite board but to say to design and make some thing that id pulled by a kite. it means you cam put a lot more ideas down.
hope this is helpful.
peter