Custom post type with custom menu

I've got an interesting situation that I am hoping you can help me with.

This is a law firm site. They have 11 Areas of Law. They want each Area of Law to look and feel as though it is a stand-alone site. We suggested multi-site. They did not want to monitor/maintain/login etc. to multiple Dashboards - too many global things. At any rate, we have been successful in creating everything but the BLOG.

They want the blog to function the same way: multiple Areas of Law each with it's own blog. This is not doable in Wordpress. I am trying to figure out a CustomPress workaround.

Really the Blog is articles written by each of the attorneys. So I thought we could create a custom post type for each Area of Law, but then that's really not much different than having multiple categories on one blog, like the currently have.

What I want to accomplish is this: Each Area of Law has it's own categories, on it's own pages, with it's own header menu, and own sidebars. If you go to the Aviation Area of Law

Notice the menu (it all reflects Aviation Law) then click on Blog (which is pointing to the Aviation category) and the menu is the primary menu.

I have tried to accomplish with CustomPress and I am still having the same issues.

How do I create a custom past, with that will allow me to use the menu swapper plugin, and also allow me to use the sidebars.

Any help is greatly appreciated.