what about sending holga's. they are inexpencive, they shoot a larger negative, and they are not one use camera's. send some Velvia, Tri-X , and Delta 100. then all that would need to be shipped back is the film. if a camera gets damaged you only lose 25 bucks.
And if the camera doesn't get damaged, all you get is a bunch of muddy light-leaky images with extreme overlap between frames