Since user created mods for the X-Box are frowned upon, and can get you kicked from X-Box live; what Mojang should do is get Microsoft's consent so that users can create mods for the X-Box Minecraft. But here's the thing, maybe Microsoft (Or Mojang) could have a terms and agreements for modding Minecraft; stating that if it can get you achievements faster, give you free X-Box live, give you the game for free, etc. then it's not allowed. If the mod doesn't affect any of these aspects then you'll be fine. Thoughts?
They could do the idea and if 4J like it then they could arrange a development deal of some sort.