there are plans to have some sort of client/server thingy in future using upnp+jsonRPC, but it would be more some sort of distributed model, where every XBMC client can act as both. There is no ETA though.
@ da-anda
that's great there are plans for some sort of client/server function. Would the function allow the user to pause something in one room and then resume it in another room? I know you said there is no ETA but do you think it might be 6 months or more like 3 years?