You can move your domain hosting very easily to Dreamhost without changing the registrar. I have a couple of .CO domains registered @ GoDaddy that I was able to host with Dreamhost with no problems. All I did was change the DNS.
And yea, that wiki is a bit confusing... it never really answers the question of "what if I just want Dreamhost to host my domain!" to my satisfaction. In the end all I did was change DNS and it worked well.