Great ideas are plain creativity, thinking, effort, observing, and a bit of inspiration. It shouldn't be matter of money or sophistication. As M used to say, "Keep it simple".
Granta's cover is just perfect, as I said recently.
magnes' is awesome. I would perhaps had designed a second cover for (non) subscribers with some curved wine bottle; otherwise it seems a little too "sexist" (to use a concept I don't really understand)... but ok, it is all about a comedy.