When I first got the idea for this, I totally wanted to write the other chapters using other fandoms - problem was that just about everything I thought of fell under "Married Couple" too! I was really amused when I saw your comment because a Harry+Hermione (friendship, not pairing, though) fic was one of those I considered writing. If the plotbunny bites, go for it! It'll be interesting to see how this idea works for the HP fandom. =D