I made a patch from your tutorial but the last part didn't work for me. Nothing happened when I did 'mesh deform' to the cage on the objects and doing another shrinkwrap made a mess. So I kept it as a flat patch: https://cgcookie.com/u/sheila5/projects/patch
sheila5 The patch looks great! Did you bind your mesh deform modifiers for the patch pieces?
I found what the problem was. The cage had to completely envelop the patch layers for the deform to work. Alas there are too many things going wrong with deforming the patch to make it look good.