Hey Bill, a while ago in this same forum I asked basically the same question you're asking. (See my post about possibly offering some promotions to current users once in a while. It's probably still on the first page of the index...) Anyway, so far the only answer seems to have been silence, which I assume I should take in the absolute negative. I admit it's also possible that nobody from Dreamhost who has any idea about the answer has yet seen the question and slightly less possible they'll see it later and answer or that something is in the works but they're set on a policy of utter secrecy so as not to tip off their competitors that a sale might be a good idea.
So no, I think you're stuck paying full price for everything, all the time, after you first open the account. Not that the full price is particularly bad, of course. There seems to be a certain subset of users who don't make much use of the bulk of Dreamhost features, though, and since I've been looking into this I've seen a couple of them take their money elsewhere. Of course I have no idea how they like their new service.
I'm sure I'd love the Dreamhost model if I had hundreds of people who I could refer to Dreamhost for web-hosting services. I don't know that many people who need such service, though and since my web-presence is mostly of a personal nature, even if I did want to advertise on it, I wouldn't get many hits. So, what works for some works significantly less well for others.