What do you mean by tested? If just playing on Cubecraft in its beta phase counts, then tens of thousands of players will have the rank.
You will soon be able to buy the Pioneer rank which will be only available to purchase for a limited time, so that's effectively what you're suggesting, just with a cost. I don't think it makes sense to give a free rank to players, since it'll reduce their temptation to buy one.
If I misunderstood your suggestion, please say so :P