Just a comment on that one... We also thought to develop a plugin, but since we are all system administrators and not developers we decided to make it as standalone solution which modifies the osTicket MySQL database directly. That is maybe also an option for you, even though it's risky and you need to make sure not to break osTicket!
If you want to know what plugin/addon we are developing I will let you know: Fetching user information from AD and add them to the user profile of the corresponding osTicket user.
How do we do it?... We added custom internal fields to the user information form which we fill directly in the osTicket database thru our PHP script. Functionality is already working, but we also want to add a interface so that you can configure which AD info should be written to which database field / additional osTicket user information field. Hopefully we will finish it soon and share it with the developers so that they can maybe implement it the correct way.
Cheers,
Michael