I think I've just finished doing almost exactly what you are suggesting, and have even paid for my license as a result..... (using the upgrade deal, thanks guys!)
I've a common library for music video and images, and have a server with these on. MC16 on the server generates the library that the MC16 clients (and other media players) uses. My MC16 clients operate exclusively under theatre view, so the solution had to be workable from the big screen.
Just using the library, and without messing with path names, worked great for music and pictures, but was next to useless for video. Large avi's took forever to load on the clients and DVDs would not play at all.
The solution was to use a common pathname on both the server and clients, and to use the play local copy option. So on the server, I load local folders using their full network path name, rather than their local drive letter/folder path, so on SERVER, I auto-import \\SERVER\Music\ instead of D:\Music\. When the client picks up the library, it uses the path information to look for a "local" copy. As it has the full network path name, it tries to read this (even though it is not strictly "local"), and loads it directly.
So you get the advantage of the centrally managed library, but with the performance of directly addressed network files.
But this all assumes a common Theatre View front end. I asked about the way Library Server worked for Theatre View queries, and the answer was that it was a mix of local config and centralised. Under the current release of MC16, Theater View queries under the standard headings (Audio, Images, etc) seem to part of the server library, whereas if you create new root items, these may be managed locally, but seem to be overwritten under certain circumstances. Might be worth playing about with this.
But if your clients need radically different Theater View front ends, I can think of a couple of options;
a) Add root items which allow you to switch between your central library for music, and a local libray for everything else.
b) Use full network path names for the music files, and just pull them into your local library, ie, without using MC16 on the server at all. This would work just as well from a NAS, but if you've already got a server, why spend more money.