This is a great start, I am going to be making some adjustments,
1) Listing the codes.
2) Allowing Editing of Code Details (Url, Descriptions, etc)
3) Allowing internal system links so you can link to secure data on the server hosting the site. Not just to a URL
4) Ability to create a dynamic number of codes (not just select from the drop down)
5) Maybe the ability to create your own codes
I'd love to commit my changes to the official plugin but if not I'll fork it and give credit to the author.