Zyora and Ragnarok
If you look at the Tieflandsburg Castle v2.esp, you'll see that there are three horses listed. Their names are Roan, Barbary and Ragnarök. Ragnarök does not appear in game (yet), I didn't feel that the player needed three horses to choose from.
It also gave me one to play around with the settings.
With the last change of the esp I opted to see what happens when you make their stats. Can you say Seven League Horse shoes? This was taken between Skingrad and Chorrol after a short 40 second ride from Tieflandsburg. Trust me I f I had kept going I'd have made Solitude in two minutes or less.