Remember when Blizzard made it so trinkets that enhance mount speed would no longer work after level 70 in an attempt to free up our bag space? Well, it seems that whole process is still in the planning stages according to Crygil:
"We don't have any immediate plans for trinkets to be used to increase mount speed past 70. It is something that we are discussing and we will have more information about this at a later date."
So unless you're a paladin, you'll have to wait and see what Blizzard has in store for mount speed. How do you think they should handle it? Glyphs? Enchantments? Something else entirely?