I know that I can use the censorship function to censor the links, but I'd prefer for the system to throw back an error to the user when they try to submit a post using a shortened link.
The error would be something like
I'm sorry, you cannot post shortened links on this site. Please submit your post again with the original url of the site you would like to link to.
I can certainly offer some money for the creation of this add-on.