It sounds more like you are trying to find a persuasive argument for someone else as to why you need a new rifle. If you have a couple reliable, accurate 30-06s that are already killing elk, how are the new cartridges going to kill the elk any deader with the same shot placement? slm9s lists several that kill elk just fine, to which I would add 7mm Mag as also very effective (and good bc).
But as others are already asking, do you reload, etc.. Unfortunately these days you can buy a rifle, but will you be able to get the ammo, dies, or components to be able to USE it? If you just want a new rifle, then you already know the answer.
