I prefer to get level 50 stones, which are usually found between levels 51 and 54, because if there were stones in zone 55, it would only saturate that zone, which is too small for a handful of players who can wipe out a group of mobs in 30 seconds.
I think the ideal solution would be to have a new map just for level 55 players, but where there would be a risk involved in order to obtain satisfactory rewards (stones, fame, etc.).