We used to cross Chocolate into many of our lines of mice -- first because the chocolate gene confers size on the offspring, whether or not they are of that color themselves, so the youngsters show better, and also because chocolate undertones enrich most colors in the gold range. One of my favorite colors in mice is Champagne -- it's a pink-eyed chocolate mouse, so the brown is diluted to a warm beige, like raw silk or coffee ice cream, or the color of an old-style telephone. I think there was a Champagne mouse on one of the links I sent earlier.
I still miss the mice a bit, but not all the work of cleaning 100+ cages twice a week. When I shut the colony down back in 2003, I traded the biomass in for one six-foot-six New Englander. Good deal; I never managed to teach the mice how to mow the lawn or take out the trash, much less contradance or paddle a canoe...
And yes, I too am a chocoholic. Aldi's grocery stores sell lovely five-packs of good dark German chocolate in small bars -- one of those will keep me smiling for a whole evening.