Wow! Didn't know Etsy had so many amazing artists. I did a search for "kid's room decor and discovered 2 artists that really appeal to me. Kathy Jeffords from TheDreamyGiraffe and Renie Britenbucher. Both have a whimsical colorful style befitting the happy kind of aesthetic I envision for our new house.
Though I love color I can't imagine painting a room in loud primary hues. The way around that dichotomy is to use juicy punches of color to accessorize the room. And these two artists provide lots of that:
It's not as nice....but I like it. Mine is acrylic paint on a small canvas board purchased from Wal-Mart.