I know this is an old post, so my apologies to those "necropost" nitpickers, but It's still a relevant topic and I have something current to contribute to those who find this the same way I did (as it was the top suggestion on my search on the subject). There is a mod, right here on Nexus, that will let you wear a full set of BOTH light and heavy armor at the same time. It's a mod that let's you craft Invisible Armor (in both light and heavy, including shields). This armor takes advantage of the slot system for a number of benefits. You can wear invisible armor naked so you can run around nude but still have an armor rating, it can be worn over clothing-class items to give you total freedom of fashion, or it can be worn with other armor. For instance, you could wear full heavy armor and add light invisible armor, or vice verse. The slots were carefully selected, it seems, so they don't take up the base armor slots but still count toward all relevant stats and perks (including Matching Set, etc.) This post help me understand how the system worked and, hopefully, my contribution will help others to manipulate said system to their advantage.