And here are some links with some very inspiring works.
Firstly, Joao Ruas. He is the one that took over drawing Fables covers from James Jean. I'll leave it to you guys to see what's similar and what's different in their drawing styles. Also check out his blog.
Secondly, Jun Tsunoda. You'd probably classify her work as fine art. But I'm sure there are lots we illustrators can learn from her use colours, balance and shapes. From giving it a try, I think abstract paintings aren't as easy to create as they look.