If it were me, and I had time, I'd probably build a switcher and mount it inside a nice little cabinet. That would make sure the switcher had all the capabilities I needed. But you can also purchase a preamp/switcher/processor that has multiple inputs. Since you need so many, your choices will be few. But there are some out there that have lots of inputs and switching options like you need.

An example is the Carver CT-17. It has 7 inputs that can be switched, and two additional tape in/out channels. It also has two dedicated A/V circuits, and they include not only audio circuit paths, but also video channels. So you might check eBay for one of those. There's undoubtedly several others, but I have one of those so I knew about it right off hand.

Wayne