We're playing around with allowing network play for scenarios over the next while. I currently have rigged together something that works simply by setting the control type in the scenario XML to "network". Additionally I display a list of scenarios in the custom game lobby that have at least 1 network player, and when selected it sets all settings to those of the scenario + sets the scenario name which then loads for all players at game start.
While testing we will need to somehow ensure that network scenarios are free of any dangerous LUA that could cause out of synch. Eventually we may need to have a way of having server controlled instructions for some LUA script logic to ensure consistency (not sure yet). But if we get this working it could open a whole new opportunity for fun for network play (mixing campaign + multi-player).
*Update: did a quick test with Elimnator using a sample scenario he whipped together and so far so good! This will make network play VERY fun and so much more interesting, but will definitely require a whole new way of thinking when it comes to scenarios since these types of scenarios are not single player focussed (message boxes need to target the active player etc). Mix this with multi-scenario loading and it gets amazingly fun