RGO, I have been through the 2 hour officer interview, although it was for RMC, I'm sure it was along the same lines.
Since my interview was for pilot, I had a Lt. or Captian who flew Hercs give me the interview, as well as a person who just sat in the corner and observed the interview. I later found out that he was actually conducting a psychological evaluation on me.
As for the details, its a great deal more in depth then the normal interview. The basics are the same, schooling, volunteer work, sports ect. but they will ask you to go more in depth as to why you did specific things, how you coped with them. They'll ask you your weak spots, things you need to improve on, and definitly ask you about the trade you are applying for and things that are happening in the CF around the world and country.
Don't bother about bringing any work with you, I'm sure they will have everythign they need. I did however bring everything that was given to me during my past visits with the reruiting center just incase. Most likely, you'll walk in there and watch them open your file and pull out your resume, go through that, pull out your references, ask you about them, go through your application form, pull out some specifics they wish to talk about. Just be prepared to explain many of things you have written down in your app. They will also look for examples of leadership qualities and experiences because you will be an Officer in a leadership role in the CF.
On top of that, they will ask you all the standard questions which they ask everyone (I know since ive been asked the same questions exactly the same way twice now). The nice long drug sheet, ask you which ones you have seen, or seen people on, and if you have a problem rooming with someone of a different sexual orientation.
That's all I can grab off the top of my head right now. If you have any other questions send me a PM.