I find it a great idea. Did you ever try fabric dye? Are you still using oilpaint or is it acrylic on the denim jackets? I noticed if I wash the denim in some cases the paint is washed in others it remains. It isn't stiff (acrylic, oilpaint I only used once). I have fabric dye but didn't come to using it yet.
I wonder if oil and acrylic paint on fabric should be fixated as well (iron or in the oven) to make it softer and more washable, although dye on clothes will rarely remain.