I originally posted this in the JobSpy plugin thread.
Kovid has decided the suggestion was worth including in the core 
Suggestion - a tool to create and copy calibre URL links to the clipboard for the selected book, something like:
- Create a show link would copy a calibre://show-book/<library_name>/<book_id> link to the clipboard;
- Create a View link would copy a calibre://view-book/<library_name>/<book_id>/<format> link to the clipboard, would need a selector drop down if the book had multiple formats.
BR