I'm sure it's been suggested before (but I checked here on Git, and didn't see it.)

Carpenters Chests.
I've always wanted to be able to make my chests have various material textures for sorting, so Like a stone chest to hold all my stone, etc.

The Carpenters safe is nice, (although the upgrade with gold ingot feature isn't working for me in 1.7.10 for some reason) but I would love to see regular chests too.

That's not a bad idea, but keep in mind the Carpenter's Safe was implemented in place of a chest. The chest uses a model renderer, which this mod doesn't support.

However, there is at least one mod I know of that can do this already: http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/1292995-1-6-x-1-7x-forge-chest-v2-0-1-formerly-colored