Don't know whether this would be 3D enough for you but I found a 'Carbon Theme' in extras devel. Still only half finished but all the buttons are done, they are really great looking, smooth and elegant, real joy to press Even the address bar in browser is done very nicely and that is usually omitted. I have no idea who is working on this theme but credit to you, I shall be waiting for the finished thing. Definitely my future default theme.