Dreamhost is great hosting provider, but it lacks one simple thing to be perfect it is user control panel
ME and my friends have some idea how to bild one using PHP and curl function and cron jobs ....
Idea goes something like this
1. You install this application on your main domain
2. you give privileges and other to your users trough web panel and store data to mysql database
3. Your users are able trough there panel to add domains, sub domains, mail accounts, databases and etc (as much as you alow them, using your admin part of script) they requests are stored in database
4. And now the tricky part ....
Once a day your script connects to panel.dreamhost.com
using your user name and password, and posts data for processing (it automates process like you did it by hand)
For example https://panel.dreamhost.com/index.cgi?tree=mail.addresses¤t_step=Index&next_step=New
and POST alias=yourmailname, domain="@yourdomainname",
First thing is it ok regarding your agreement and other policies to create this script
I have not found any problem in this