[cinq]

Something like that I am doing for my site now but briefly :

You could create a db table to house the additional information for each post.
Make changes to newthread/newreply templates for the new fields, eg. 'Required Stuff:' is a input text box.

In the newthread php file, you then insert the data into this db table you have just added to store the additional information.

After that, you would have to change your showthread/showpost/postbit(?) files/templates to reflect this additional information by querying the db table for what you need.

Not sure if that makes any sense