Glad you asked this, I've been wondering the same thing myself lately! I am just getting into pattern making (and building a website to share them from) and I am planning on doing many of those less seen ideas. I want to have a "religion" section that includes atheist/Humanist, Buddhist, Muslim, Christian, and whatever else I find fascinating and fun (it needs a different name still working on that - maybe the suggestion of "Cultural"?).
There is a couple artist out there with beautiful multi section plaques with bible verses on them. I love the look but, well... bible verses just don't fit in my house... I want to do a similar idea with verses from other religions or quotes from Carl Sagan and the likes.
Along the same lines I also have several F*** Cancer type items in both censored and uncensored versions. I rarely see anything uncensored language wise and sometimes I want it that way (and have customers that do too).
Anyhoo, I hear ya and I'm working on it!
And great job on the Darwin fish, I love it!