Theme login page

I currently pull the Duo module into our distributions, over 9 of them, via Drush makefiles and in order for the Duo login screen to be updated to look like our theme, I would have to fork the entire module and keep up with any patches or updates manually. Currently if someone changes the login page theme and then updates the module the files would be overridden which defeats the purpose.

If the login page could be themed in a way to use the site default theme or at least created using .tpl files that allow overriding, I would be very appreciative.