Really quick, and generic...
Using a Wordpress/BuddyPress combo (since I have recently invested about half a grand in themes and plugins), can I make the following scenario happen?
Let's say that I want to have "domain.com" using "theme A" for desired content appearance and functionality. I'd also like to have a "community" subdomain (or directory---whichever will work for this scenario) with "theme B" installed for Buddypress. Then, I'd like five other subdomains (or directories) with "themes C thru G," also used for specific content appearance and functionality. Lastly, I'd like the members of the Buddypress site to be able to utilize "same-account" access to author comments on one of the other sites, or write a blog post (if given permission) on yet another.
How might I go about doing this?