I'm gogin to go out on a limb here and say no.
DreamHost relies exclusively on Debian as the OS of chouice for servers.
No MS means no MS Sharepoint.
Have you considered Google's collaboration tool "Sites" it has many of the features of SP and is free, and works with domains hosted on DH.
"To be pleased with one;s limits is a wretched state."
-Johann Wolfgang von Goethe