Maybe you could try sewing them yourself. Take two equal size pieces of material turn them on top of each other with the outside facing out. Sew around your square leave an opening to put beans in, turn it rightside out and fill it with beans. Stitch up the hole. Or, try a small sock or footie filled with beans and then you only have the hole to sew.
Not an odd request to a seamstress if you can find one. Good luck!