OK, here's what I'd do based on what I've tried so far in getting iMovie .dv files into FCE and avoiding having to render.
- Open your iMovie .dv file in Quicktime Pro.
- Extract the audio track
- Export the audio track as a Quicktime Movie, Linear PCM format, Channels Stereo (L R), 48kHz, 16bit sample size
- Delete the audio track from the .dv file
- Open the exported audio file, select all and copy.
- Select All in the .dv file
- Add the exported Audio file using Add to Movie
- Export/Save As the .dv file as a self contained Quicktime Movie
- Use this movie in FCE
The benefit of this approach as opposed to exporting .dv file in one go is that the only thing that is truely exported, etc is the Audio track which is relatively quick. The video track is left unchanged so there is no loss in quality.
The resultant file never has to be rendered in FCE.