With an option like this clearly visible, might this be an acceptable way to make money with a Chrome extension? There certainly don't seem to be many options available for developers, apart from the other highly annoying way of periodically throwing the user to a "your extension has been updated!" page with ads on it.
Not in my opinion. I think you owe the user a clear indication about that it is an add, and from who the add comes. Just modifying pages like that is malware behavior.
If they clearly tell me it's their add then I can chose if I want the extension or not, so removable adds is less of an issue.
