I recently shot video in the Canon 7D's 640x480 mode. I took that footage, converted to AppleProRes and edited it in Final Cut. The final video runs at about 94 minutes.
When I try to export from Final Cut (Quicktime Export/Current Settings) I either get a General Error or a File I/O Error. I tried sending the sequence to Compressor and exporting it there (Apple ProRes) and I get a 94min video file that's just a black screen with about a second of audio that loops itself for the entirety of it.