@Dopedangel - there is another option that I will just throw out there for your info. The Goodreads Sync plugin has exactly this capability as part of adding to a shelf. So I have it configured such that when I finish reading a book I do a right-click to add it to my read shelf - the dialog that pops up gives me the opportunity to override the date read, and I also have it configured to assign Yes to my boolean column, all triggered from that one right click.
Of course that does rely on setting up a (free) Goodreads.com account as well, but you might find it of interest to track your reading/stats through their website as I have.
It might not be of interest as a complete solution, but it does do exactly what you mentioned in this thread.