One idea is to have the handprints serve as the pedals of a flower and to paint on the stems and grass yourself. This project is also great for aprons, pillowcases, etc. Whatever you can get paint to stick to, go ahead and experiment with it. Just keep in mind that you want to be practical in what paint you use and how much of it you use, the last thing that you want is for the handprint shirt to get ruined or to ruin other clothes when it is put into the wash.