I've never used candy coating and I'm not too familiar with it, but I've heard about it and I'm pretty sure this is what you want: NECCO® - Our Products: Eagle Brand Chocolate Candy Coating
Does that help? Try a google search using keywords like chocolate candy coating, candy bark, baking blocks, and so on. As for where to find it, I have no idea. Sorry I can't be more help but I hope I at least pointed you in the right direction!
If you absolutely can't find what you're looking for, post your recipe here and I'm sure someone will help you find a way to make it with other ingredients.