As ryecoaaron said, Plex and minidlna are servers that stream to clients using DLNA rather than relying on NFS/SMB. They allow you to consolidate multiple sources under each "library" (eg. TV, Movies, Music, etc.) you create.
Quote from "ryecoaaron"
I am changing snapraid to add its own samba share for the pool just like greyhole adds samba shares. I will also add a button in the commands tab to execute the pool statement. All of this is why I am working on an aufs plugin which would be a read/write pool. Then you wouldn't need the snapraid pool.
Awesome news ryecoaaron. I have played around with aufs a bit and I like that it supports pretty much any underlying filesystem without introducing CPU overhead like mhddfs (a FUSE filesystem). I look forward to trying out the plugin. Currently, I think aufs is the best alternative to something like Greyhole as they provide quite similar functionality with aufs being a lighter weight option that doesn't require dependencies like MySQL and also allows NFS (Greyhole is SMB only). I will have to spend some time to see where the real tradeoffs are.