Sounds like a useful extension that I might have liked to try (I'm using Chrome). But I'm wary of extensions that I need to load from other locations than the Google webstore - the webstore at least provides some guarantee against abusive extensions (or that become abusive after a while).
You say that the it "infuriates you" that Google demands payment for adding an extension to the Chrome web store - but it's only $5 FCOL [0]. Their motivation is purportedly to stave abusive extensions, and it might actually work like that to some degree (as well as contributing minimally to their cashflow). But regardless, $5 for an otherwise free service that gives you a much farther reach than your current method - might be worth it.