RE: two domains on your account having the same IP
It's actually not super likely. Each of our machines have lots of instances of Apache running at one time, and each instance of Apache has several IPs for VirtualHosting.
So even if they're on the same machine, and by chance end up on the same instance of Apache, they still might be on different IPs.
However, we do have our own globally routable IPs from ARIN, so it's not hard for someone tech-ish to figure out you're hosted here.
Well, plus even though your domain resolves to an IP doesn't mean it resolves that way in reverse...if you're on the basic-bongo instance of Apache on apok and you do a reverse lookup of the IP your site resolves to, you'll get basic-bongo.apok.dreamhost.com.
So, yeah. It's not like you can easily pretend you're not hosted here. A dedicated IP would help a lot, but still anyone technical can figure it out quickly.