BTW is there a way to copy them to the clips pane and not the timeline?
I don't believe it's possible to Paste clips into the Clips pane. iMovie HD Pastes clips at the current playhead position. There nothing that keeps us, however, from moving the playhead to the end of the project, Pasting, then dragging the clips to the Clips pane.
(It makes sense iMovie does it this way because we normally want clips Copied together to be Pasted together. For example, when we copy both clips and transitions together. Pasting into the Clips pane wouldn't allow those clips to stick together.)
Your findings about the trash are interesting. Like earlier versions of iMovie, iMovie HD does Media file management all on its own, and sometimes it's a bit of a mystery. It will discard files the project no longer needs. When doing that, there are times it moves stuff from its own trash to the Finder trash. In the test I just ran, I Copied an imported image rendered by Ken Burns to a second project. When I Quit without saving, Movie HD moved the copied DV file to the Mac trash, but kept two versions of the image file in the iMovie trash so I could rescue them from the iMovie and re-build them.
Karl