I would have thought it unlikely. IIRC, for DLNA the setup handshake between the media server and the renderer involves broadcast udp, which is hard to route when outside of a LAN.
There might be some way you could 'hardwire' the server and client ips so no handshake was required, but that's likely to be a pretty minority activity, and I doubt (but don't actually know, I'm just conjecturing here
) that would be part of the main feature set.
If one of the PMS gurus has a definitive answer to the contrary, I'd like to know as well, as I originally had 2 networks with my PS3 on one and my server on the other, but the handshake bust that plan as my router is too noddy to configure this. So I just plugged them both into the same LAN to solve the problem... Ugly but effective