I've been doing some exploratory work on how I might implement the designs in #603. Even without any UI changes, I thought it might be useful to open this for an early sanity check on my approach of knowing all conflicts before the dialog is created.
The patch works by teaching copy/move operations to add each conflict encountered to a list of FileConflictInfo instead of running the file conflict dialog in place. Conflicts can then be processed as a batch and sent back into the copy/move machinery with their FileConflictResponse already set. This commit leaves the dialog itself working as it currently does.
Beyond this, my rough plan is to repurpose NautilusFileConflictDialog as the a multi-file dialog based on the mock-ups and implement a new GtkMessageDialog subclass to handle the single file case.