Yes, I definatly reccomend E-mailing support if you can't get to the panel. I believe you can't E-mail support at dreamhost.com any more, but the contact.cgi form on their page will get your message into the same que. Just be sure to provide them with information so they can find your account.
As far as the panel "server" it's actually a pool of several high speed computers working togeather.
For me a subdomain normally is functional with in 5 to 15 min. It's a bit more than a tweak to apache though. Apache has to be configured, a httpd_conf file generated, directores for logs and the website has to be created, and the thing that probably takes the longest is that records have to be added to the DNS for the new sub-domain. It used to take upwards of 2 hours for a change like this to go through, but now I've had it work as quickly as 2 min.
art.googlies.net - personal website