Keep in mind that this is speculation only, consult a professional, yada yada. But the first thing I would worry about would be navicular. Generally that's more associated with long toe / low heel syndrome, which isn't really the case here, but you're amplifying concussive force onto a smaller area and that can't be good.
For more professional responses, I'd urge you to check out horseshoes.com
and see what the experts there have to say.