I would love to hear responses, too, but it appears that's not going to happen. I have looked and looked. It appears we will have to hire custom coders/programmers to do this for us. Apparently, there is no plugin. When I first mention it, people stop listening and just say, "BuddyPress. That's what you want, BuddyPress." And I wish it were true, but it's not. BuddyPress may do a lot, but it doesn't do this. Now, there is a site called Groupsite.com. It allows you to build profiles/portfolios like I want. It appears it's also willing to give you a group with it's own private settings. I'm investigating it as a solution now. It's not free, but the fees I see seem reasonable, unless they scale up fast according to the number of members you have.
I hope this helps.