It exists already.
In Python. Which is OK. Not my choice, but it works.
I could be wrong in my reading of The Spec, but my interpretation is that Gnome now follows the FreeDesktop.org specification.
If I set an environment variable, $XDG_DATA_HOME, to $HOME/.local/share/Trash, I think I'm mostly there.
But I'm fine for using the normal graphical means to empty and recover trash. I'll try it and get back to you.