i have seen a notebook being airbrushed before and it look so nice. it was pearly black (with purple) and with silver logo. so you got something like 2 tone color cause cause is a mixture of 2 colur
but it's better for you to do it after the warranty expired

that's why it's better to mod after the warranty expires but the notebook i saw being airbrushed is the prettiest notebook i ever saw...dunno how the guy did it. did i mentioned it was gloosy as well? yah, it was gloosy with 2 tone colour

another way to do it is design yourself and send it to printing shop to print for you by using high quality material (like the normal laptop skin)
then just stick it nicely. if you measure up all the design and edges carefully, you should be able to come out with a nice one