I agree with the poured fondant, it's also what's used to cover petit fours. If the cooking temperature is accurately regulated it won't turn to hard candy like the previous poster's experience, it was just cooked too long.
A quality cocoa powder (such as Ghirardelli) can be added to your standard buttercream to make it chocolate but I prefer to add cooled melted chocolate instead after the frosting texture has lightened up and it's just about ready to stop being mixed.
I haven't found any worthwhile in G'boro or High Point but there's one southeast of Raleigh called North Carolina Paper Co. that is amazing. The website is www. ncpaperco. com without the spaces.www.ncpaperco.com(mod edited to provide link.)