For static websites, automating Dreamhost2X turns out to be quite straightforward (for good choice of X) but the Dreamhost api seems to be missing some crucial bits needed for automating X2Dreamhost:
for example, while there is a way of adding dns records (not that I've tried it yet), there seems to be no way of adding domains and/or subdomains
(nor indeed a way of adding users, which would be highly desirable since one generally wants to add a fresh domain onto a fresh user).
Surely there must be a way of doing this? It's hard to believe that nobody has ever moved a domain to Dreamhost in an automated way.
(Also missing is a way of updating nameserver info, but a simple workaround is to keep one's registrations somewhere else that does have this functionality, which is anyway an often-recommended course for various reasons.)