Safari on OSX & iOS does do random password suggestions, out of the box.
My Thai business banking system is paranoid and disables autocomplete, paste, etc, even with the security of a physical token), but the one that really annoys me is things like Basecamp - I had to futz around and disable JavaScript for a login to be recognised and prompt to save a password - by default it does an XHR which doesn't trigger the "save password" prompt.