Man, if a guide told me my 270, 280ai, or 30 06 was too small for his liking, I would likely not hunt with that outfit.

In your case since you have deer rifles, I'd buy a bigger gun just for the hell of it, doesn't mean you have to use it for elk haha. Thinking 300 win, 35 whelen, 338 win.

For someone who needs a rifle to mainly hunt deer and hopefully elk and does not have a rifle for this, I would have to suggest the 270 or 308 in a good fitting rifle that catches their eye.