I made a modpack for 1.10.2. That has both ProjectE and MCA. These two are required for the trick. Other requirements: Required core mods, 1 diamond, 4 redstone, 7-9 iron, and a village.
Not sure if regular villagers also have trades like these but MCA guards and blacksmiths have trade for 7-9 iron for an emerald. Know if you have a philosophers stone from projectE. A philosophers stone requires 1 diamond, 4 redstone, and 4 glowstone. Then traded the iron for an emerald and place the emerald in a crafting menu with a philosophers stone. keep doing until you get a stack of iron. Giving you a profit of 57 iron. Repeat for even more.
the modpack is http://www.technicpack.net/modpack/my-last-modpack.942765.