Sometime ago I had an plugin custom designed for me for Xenforo 1.0 - a rather simple plugin that just added a field below the post area for a citation for a debate. That forum closed down when my schedule became too tight to admin anything. I recently restarted the forum and I've found that the plugin no longer works. I am now running Xenforo 1.3 respectively. It has a line error where something is taking longer than 30 seconds to execute in the database. I wouldn't imagine updating it would be that hard for someone knowing what they are doing. The plugin is already written. Just needs an update. Please PM me with offers.
You probably want to hop up to this https://xenforo.com/community/threads/custom-fields-by-waindigo.34093/ N>
Not sure if I can use that Nigel. This particular plugin basically puts a single field under the post box and offers the option to create more fields. Each field is to insert a URL for a debate source and then each URL is placed in a list at the bottom of the post. It was a nifty little trick for a political forum. Came in handy often actually. If you want to take a stab at it let me know. I can just skype you tomorrow if you want.
Sure just drop me a skype. I changed the url in the link above as well. I believe that is exactly what that stuff does though. Adds custom post field for a url or whatever. It now does a range of other things as well you may not need but I can likely flesh out the old one. I will be around tomorrow. N.