I don't want to cast from the cloud . Just make the device able to receive any media from my LAN!! it's nice that the dongle can stream from the web, but it's way more useful to make the device aware of upnp/dlna devices over my local network. Because of this I've moved to raspberry which - exposes itself over the network as a upnp device - plays remote media in the main TV - acts as a nas, it can stream to kids' roo…
Chromecast accepts URLs to LAN resources. All you need to do is expose your files over HTTP (I do this with my NAS and it works fine).
What app do you use to do this?