Our hypothesis about Guide du Routard was correct! Somnio was indeed written up in their 2010 Barcelone Guide. The write up (translated from French) goes something like this:

A brand new little place with contemporary charm and elegance with a special guesthouse atmosphere. Pleasant rooms with beautiful wooden floors, beige, chocolate and blue-gray hues, with or without private bathroom (the bathrooms are very modern and well-equipped!) Good bedding. That said, the rooms lack closets. Prices are slightly overvalued, but the kindness of the owners almost makes you forget about it.

Now we're trying to figure out which author visited us. The book just arrived in the mail, so I'm at home reading the names over the phone for Lee to look up. I'm enjoying using my thickest fake French accent. It's a fun game.