This pattern is for a VERY SMALL stirrup bag.  If you subscribe to the Leathercraft Library premium videos, there is an instructional video on how to make a stirrup bag.  Attached to the video is a pattern you can download for a MUCH LARGER stirrup bag.  I made this one a couple of years ago. 
Also if you are feeling crafty you can sit down with a pencil, ruler and some poster board and make your own pattern, It's a pretty simple design