It takes is a dedicated multicast relfector and few firewall rules to let you discover your media devices and stream content.

I'm not sure if I'm naming the right one..? "vlan?" (I know or assume some routers "do" have this feature) But with wifi easily hackable WEP and some parts or all parts of wpa? Why don't router ...

All the info I've so far found insists on using the "router on a stick" scenario for any communication between different tagged VLANs. Communication between any VLANs requires a router of some kind.