Seems like this would have been discussed before, but I couldn't find it using the search function. How much trouble is it to cover a dark chocolate cake/chocolate buttercream with a light colored (light blue in this case) fondant? Should I just roll the fondant thicker or will that not keep the color from coming through? Thanks!

I've never had a problem, and all my cakes have chocolate ganache underneath the fondant. The white three tier wedding cake in my album was dark chocolate ganache covered with just a thin layer (about 3-4mm) of fondant, and it didn't show through at all. If you're worried, just roll a little thicker than normal, or if you're planning to emboss the fondant you should roll it thicker, otherwise the chocolate may show through embossed areas.

Thank you!