My apologies if this has already been addressed. I don't see a way of doing this in the current versions...

Would it be possible to import an existing project as a clip? The powerful thing would be if any changes to the original clip would be maintained after it is placed in another project.

This would be really effective where small sequences of video were used in a number of other projects - a title or ending sequence. Very good for a series of videos

The title or ending sequence could be editing and these changes would be reflected in the projects that contain these sequences. It would only be necessary to rerender the projects that contain the imported project/clip to reflect the changes.

Could this be done by importing the data from one project file into another?

You mean
Project > Add Clip > whatever.kdenlive
?

Hello,

Yeahhh, that run for me, just unbelievable, supercool.

Etienne

Wow Thanks ! It works like a charm :)