Recently, I got an e-mail asking about the custom illustrations available at the $20 reward level. Someone asked if the illustration was something created at my discretion or if backers could request something specific.
My position is that so long as the request isn't absurdly complicated (the cast of Saved By The Bell in a steel cage wrestling match with a gang of Wookies), I'll draw whatever you want. It could be your favorite Theater Hopper character in costume, it could be Jason Voorhees threatening your kid sister.
Keep it reasonable and inoffensive and consider yourself gold.