Maybe they could be used to make a redstone-iron wire? (Basically works just like redstone but can be placed floating, like a block, so that crazy redstone torch towers aren't needed to go up or down with redstone, as this was always an annoyance for me. This would help compact a lot of builds.
That would be cool, and they wouldn't need repeaters.
Iron nuggets are a recently added item in minecraft that seem to serve almost no purpose, they can be obtained by either smelting an iron tool, weapon, or piece of horse amour, or putting an iron ingot anywhere on a crafting grid. Should they be have more uses? Please specify.