Long time lurker here!
I've had this idea for years now, and I've been putting it off since forever so I figured I would share it with like-minded people so it could perhaps become something one day (or not).
Basically, I like horse TF's because horses are big and muscular and they are real animals we can all relate to. My whole fascination with TF's started when I got into werewolf-fiction as a kid, but it went straight into high gear as soon as I was exposed to the Incredible Hulk 80's cartoon. The transformation sequences in that show were amazing and really highlighted the anatomy and muscle-growth, which of course I think is fantastic. They are still probably my favorite TF sequences, if it weren't for the fact that it was the Hulk...
Here are some clips to show you what I mean:
https://www.youtube.com/watch?v=FqMlJsa2M_0
https://www.youtube.com/watch?v=E_qIBSWEZjg
Of course, these sequences are very short, but you get the idea.
Don't get me wrong, I do like the Hulk as a comic character, but as a subject for a transformation there just isn't a whole lot of change going on except for him growing bigger and green. That's why I think a horse TF in this style would be awesome, because the change is far more drastic and therefore adds a greater element of "humanity loss" to the mix. I personally would prefer the subject to be female, because again: it makes for a stronger contrast since females are typically less muscular than men.
This is an idea that has been running through my head ever since I was a kid, pretty much. I'd love to see this idea become a reality one day, but of course I don't hold my hopes up for it. I wouldn't mind commissioning somebody to animate this for me, but some of the prices I've seen for short animations are too high for my budget. I could try animating it myself some time (I'm an artist) but I don't have a graphic-tablet, so I don't think this is feasible.
I wanted to share this anyway to see if anybody has ever had this kind of idea before, or maybe if there are horse TF's like this that I just haven't seen. Who knows!