Just a little thought that went through my mind. Maybe add at NPC at home by the runecrafting dark mage that will exchange combination runes for the normal runes (Ex. give him 100 water and 100 earth runes and get 100 mud runes in return) obviously the amount received could vary for balancing, as in maybe half the runes (50 instead of 100 received in the previous example) This would also be available for Ironmen to use as they would have to have the required runes before hand anyways.
Thoughts?