I have discovered that others have used the phrase “viva la evolucion” and have made it into tee shirts. They’re cool, having the classic image of Che, but as a chimp, with the slogan underneath (one shown below). They can be bought at a number of websites; rather than recommend one, I urge you to Google “viva la evolucion” and choose one. I’m doing it!
Addendum: an alert reader (see comments below) has found the tee shirt with Darwin’s image at Cafe Press, here.