I use the SingleFile extension, ~~which seems to rely upon an external site (could be wrong about that - I've never bothered to check)~~ (EDIT: update below) to download the webpage and store all the contents within a single HTML file which you are then offered to download locally (there's also a variant that compresses the contents using ZIP, but it seems to have significant compatibility issues - at least in my experience). The source URL & download timestamp are inserted near the top of the resulting HTML file's source, but not displayed as the actual content. Would that do?
EDIT: I've finally just checked, and according to the FAQ it does not use an external server - even though it presents like it does, IMHO. It does warn that it may reach out for items which (for dynamic pages, or whatever reason) hadn't been downloaded previously when creating the saved version, however.