This idea will probably get shot down, but maybe a rank between gold and diamond would be nice. If a gold wants a higher rank, he/she has to shell out a LOT of money, as compared to the rather small upgrade from iron to lapis or lapis to gold. It's a simple idea and I don't expect it to be added, but it would certainly be nice to be able to support further without having to pay what is for some people an entire day's paycheck.