1974 Duster t-top conversion

I have a '74 Duster, and I am planning on giving it t-tops. It's going to be a replica car from a movie. When I started this project, I thought the car had a frame. (T-tops would be easy to do if it did.) Then I learned it's unibody, so I know if I cut out those chunks of the roof that I'm messing with the structural integrity of the car. I've asked around, and I've received several different answers:

1. No modifications necessary.
2. A heavy duty roll cage will have to be installed.
3. Reinforcing the frame along the bottom of each door with square tubing will be sufficient.
4. Cut off the entire roof and weld in a replacement t-top from a Trans Am/Camaro/etc

So I thought I'd ask here. I know it's an unusual idea, but still, I hope it makes for a good discussion. Any help would be appreciated!

- Dave