No I am not a developer, but I am somewhat knowledgeable on what can reasonably be done, making a moving object is basically creating a new entity and rendering a .png file to it, there are a lot of mods that do that. So far Gravitation Suite, ThaumCraft 2/3, and one IC2 addon made for the purpose of a HUD, are the only things that I have ever seen implement some form of a HUD, logically the difficulty of coding a HUD must be higher than making moving objects. If this was made as something built in to a nano-helmet or a quantum-helmet (which has already been suggested once by the way), I would see greater use for it than it being a stand alone item. As it stands, I just don't think that there is enough justification for making an item for this purpose.