Just discovered that if you hold sneak whilst on a horse your horse will walk (trot)

probably common knowledge but cool finding out.

your horse also flys with levetation

You can also ride your horse inside buildings if you teleport while on the horse. You can blow through dungeons pretty quick.

If you cast a fortify speed spell on yourself...with your horse run faster? aka, does your speed effect the speed of a horse?

'using' cloaks and robes will pull the hood up/down...

No, horses have a set speed.

Same with various shirts and such, they will change styles when you use them. Daggerfall has some very interesting features!

I was able to layer 2 cloaks on my argonian to achieve an interesting effect by making them 2 different styles (one behind the shoulders and one covering the shoulders).