I would try it. Interesting idea putting two popular beverages together. If they can knock out the caffeine and keep it lo-cal... might be a big winner - depending on the taste. I like the combo of half coffee and half hot chocolate, so I would be curious.
I just tasted this the other day! At the free-taste booth at the supermarket. Not sure if it was Coke or Pepsi though. It tasted ok, like cola with a subtle hint of coffee. I'm not a soda or coffee drinker myself. Guess this is for people who need a double fix of caffeine fast ...