I think for an e-mail campaign to work, we'd almost need some kind of a robotic piece of software to to do. If we get even a couple handfuls of people to write a note and they all hit a manufacturer in a 2-3 period, it'll look like a "campaign" or worse, it'll look like one crazy guy who has control over a slew of different e-mail accounts.
What we need are multiple e-mails from many people, re-written and re-worded and re-sent every month or so. Something that hits them over and over again, from different directions, so it actually occurs to them that there is demand for it.
Even still, there is a realist in me that knows what I like and want but can easily see that it likely doesn't make fiscal sense for these manufacturers to do it (necessarily). I'm not a bean counter and I don't have an intimate account of the kind of overhead there is in manufacturing to introduce a new product.
We are a small group. If you added up the grand total of every man, woman and child on earth that has ever actually purchased a .327 Magnum chambered handgun in the history of time... it would probably be about one week's worth of 9mm handgun sales here in this country.