john if you can make an actual good looking level editor for iphone, hands down. in theory its not hard but the screen is just too small. unless apple decides to increase the screen even more you wont get a decent one working.
yet emeras suggestion would be the same to do it in a GUI first. that way it could even be given to players which could send the level itself via email to their own (from the graal client) or upload a picture on FB.