What I want to be able to do is store music on any one of our computers, and access it from every compuer. Ideally the path to access a track would be the same on all computers. When a track is added to on one computer, it would automatically be added to all of the others.
In some ways what I am looking for is a distributed file system like Coda. This would allow music to reside on some server, but be accessible by a bunch of other server. Coda also allows disconnected operation. (But I don't think that this works well with large media files, as each disconnected computer would need to keep a cache of all of the content.)
AudioManage is a windows application that lets you do this as well. It creates a virtual file system where you can drag your media files. The files system then contains the meta information for the tracks, as well as the reference to the actual file themselves. This allows you to create views into your music, that cross multiple file systems. When you actually want to access the contents of the files, then Windows follows the file systems reference for the contents.
One additional difficulty with my situation, is that I want to have access to this content from outside of my house. For example, when I am at work, I may want to listen to a track on the Mac mini. The problem here is that our cable modem has pretty bad upload througput. So when accessing the file remotely, I is not possible to have the data transfer rate keep up with the playback speed.
Now I am curious to see how Amazon's S3 service, through applications like JungleDisk, to store this content. Using a hosted site like this would allow faster access from anywhere. This S3 file system could be mounted on all computers to allow simultaneous access.