In reply to:
What i want to know is IF it is possible and/or allowed to install your own CP?
I could be wrong, but I don't think this is possible on the shared hosting plans.
It would of-course be possible on a dedicated server, but unfortunately DreamHost is not currently able to supply these (well, not directly anyway).
For the definitive answer to this question I think you should ask DreamHost themselves using the link below. While DreamHost staff do sometimes post on these forums, it is mainly a user to user forum.
http://www.dreamhost.com/contact.cgi
Mark