Show-horse....Show-girl. That works. The fancy horse-gear looks perfect in this costume. ('Cept for the frills on the strap across her cheek. That almost looks like one of those old-time sideburn/beards. winking face) And I like the mane.
As for the drawing as a whole... Above the waist it looks good. Below, not so good. Man, those legs are short. I guess if she's supposed to be an anthro pony.... And I kinda wanna see how you do the hooves. 'Cause this is a neat idea, and you did a good job of pulling off the rest of it.
A ponee =O Good anatomy, way better than me. I...are jealous.