The patch above (crudely) allows non-users of a LiveJournal site to leave comments with their name. email address and website attached and have the opportunity to authenticate their contact information. I've only done a small amount of testing so far, but nothing exhaustive. There's more information at the zilla address.
If you have questions, comments, or suggestions, or have a development server that you can test this with, I'd appreciate it if you leave your feedback here or on the zilla item.