I'm not a big fan of Trashcan myself, but then again when using Mac OS or Windows I tend to rely on it (for example, the fact that removing a file in XCode will land it in the Trash is quite convenient). So, to sum things up, here's what I'm offering to do:

1) Add Trash functionality alongside Delete to Ambient's menus, etc (or make delete take an optional parameter controlling what happens with the file)

2) The same functionality would be exposed to applications via the wblib

3) The Trashcan functionality would create a .trash (or so) directory on each volume when moving files to trash. That means any (writable and local) volume would support the trashcan functionality, no matter what filesystem the volume is formatted with. No files would ever be copied between volumes.

4) All trashed files would be viewable in a single place, in a virtual Trashcan folder showing trashed files from all mounted volumes.

5) Files could be automatically restored to their original locations.

Point 1 implies this will be entirely optional and likely disabled by default.