Here's a version of mine. It's a really simple one.
Zipped PHP file
To set the custom page you have to manually enter it's full path into line 30 and 69. Then you have to overwrite the original PHP file at
plugins/system/forcepasswordchange with this one.
Note that this version allows the user onto the site if their submit a form. ANY FORM. It means if you have more form on the page (even the login/logout form), then it can be fooled by clicking it's button.