I really need to start taking more pictures of things i do when i play. Not too long ago i did some crafty projects with the family, we made faux batiks and did some water color like painting on fabric. For this we went with watered down acrylics and painted the fabric after we fused it to some freezer paper so it would act like canvas. Turned out really cute. Then we used our scraps to whip up a doll blanket for my daughter and so far it's washing well. I am really tempted to use the same method to make myself some dresses since warmer weather is coming finally.
The possibilities with coloring fabric is really endless. I hope you have fun with it. You have a great idea and it sounds like it will be beautiful and very meaningful.