I've searched now quite some time for a solution for what I want but I can't find it so far. So let me describe what I like first. Maybe someone has a starting point or recommendation for me.
I like to have a central storage point (CSP) accessable via WiFi for my big file collections: iTunes library, Aperture/iPhoto library, Backup, etc.
The iTunes library I want to access via my Mac, iPhone, iPad,... I would like to be able to stream the content to AirPlay compatible Hardware (Speakers, TV, ...). Example 1: Grab my iPad, go to the Music App, look under shared libraries, pick the one on my CSP and tell it to stream it on my iPad. Example 2: Grab my iPad, go to the remote App, select my CSP library and tell it to stream the music to some AirPlay speaker.
Additionaly, I like the CSP to serve as a router. Means: It is the one that provides the WiFi and there is no need for an additional device.
I would also like to be able to access it via VPN/DNS so that I can use the CSP as a personal Cloud, always accessible from anywhere.
What I have found: I could use MacMiniServer. But this is energy consuming and a complete overshoot in my eyes. I do not want an additional computer... Then there is the Synology DS213 Air, which comes closest I think. But I am not sure if the library sharing works as I want it (it doesn't a couple of months ago but maybe it is able to now). Does anybody know that?