I'm going to try harder and spend more time creating painted pieces so I'll eventually have a portfolio for concept art.
Here's an Atlantean skin idea for Vel'Koz. His high movement speed animation always reminds me of jellyfish, so I've been wanting to do an underwater theme for quite some time. However, a jellyfish theme wouldn't exactly work without adding a lot of extra flowing parts. Instead, I took influence from the Atlantean Fizz and Syndra skins, giving him an armored and finned gold headpiece, plus shoulder armor inspired by murex shells.
Posted on the boards here: http://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/R1tBLmon-atlantean-velkoz