I started this little test to find out if I’m able to dynamically change texture (of defuse pass in this example). I came to conclusion (which i found out is included in Bartek’s tutorial which was inspiration for this) that i can’t have UV pass on edges of mesh. Well, it works technically but its definitely not pleasing to eyes 
:D. It works however for the cap since its not overlaping the edge…
(cover author Dominik Hron)
Still, this learnd me some flexibility since the color pass can be rendered in internal, while the rest is rendered in cycles. When there’ll be an animation, i can render light paths and so on and combine with separted blender internal rendered defuse color pass. Cycles multi pass render is saved in multilayered exr.
If you are interested in a bit messy and simple composition.
Open for critique and suggestions (i can provide UV map .png to make your own cover and render it out and post it here!)