I've probably said it before, but one of my default "I want art from you but don't know what to ask for" requests is my avatar character McClaw. (It's also a way for me to gauge an artist's style.) The references I use include descriptions for fantasy, contemporary, and science fiction settings.

Here is the result when I caught Brian Reynolds at Furry Connection North this year (2013).

Art drawn for me by  ToonFX during FCN13.