Not sure about diy juice combos for chocolate yet, but as someone who plays around in the kitchen I can tell you this, couverture chocolate (your higher grade choc, lindt, godiva etc.,) has a minimum level of cocoa butter of 32%. There are usually also milk solids, other oils (the more of these the further away from couverture chocolate it gets) and varying levels of sweetener. The cocoa butter gives it the "body" and richness that spreads like silk on the tongue. (Chocolate by itself is flat and bitter.) Not sure you can get that exact flavor with just using chocolate flavoring even with the addition of vanilla. Flavor additives (to my palate anyway!) tend to be 2 dimensional by themselves but when combined with other things like fats and sweeteners develop a roundness that's tastier. With that in mind, I am def going to try to mix some vapable chocolate concoctions. I ordered some flavorings from WL and hopefully I picked a workable combination for chocolate. We shall see... 
