Over the past decade I've seen hoof mitts go from relatively esoteric pieces of tack to the point where molded rubber hoof mitts can now be purchased from multiple online (and brick and mortar) BDSM retailers. If you look around these can be had to $100 - $150.
More recently, I've seen leather hoof mitts start to appear more and more often in photos of ponygirls. Buck at the Water Hole used to make leather hand hooves for pony play, but I think they were discontinued at some point in the last few years. Currently, Fury Fantasy is the only place that makes leather fore hooves for ponyplay.
However, I have other leather hand hoof designs in various photos online, so I expect there must be another manufacturer out there. Of course, it's possible that they are all custom made. Although I loove my rubber hoof gloves, I really do want a leather pair as well. Thus, I decided to try modifying a pair of puppy play fist mitts, which worked out surprisingly well. It was fairly easy to convert a puppy paw into a pony hoof by removing the pawprint pad and gluing on a small horseshoe.