What about this as a possibility-
what if each player got a chance to 'shut-down' someone's communication? I'm thinking that right when a spring season starts, 1 (or 2) players send a message to another player stating that their communication to [receiver] has been shut down for the year. They can do this immediately if they are smart, or if they drag their feet then it is simply unfortunate time wasted for them.
Everyone will know who had the ability to perform the.. shall we say... 'comm-attack' during that year, but noone will know what line was shut down (except of course for the person's who's comm was shut down [sender], and that was only between 1 other player, the [receiver]).
For example, spring '01 Italy has a comm-attack so he sends Austria(sender) a message stating: "your communication to Russia [receiver] has been disabled." The receiver will not hear anything, and will just be lost in confusion. At the end of the year during the build phase, the 'comm-attacking' country will announce what line was disabled, to clear up the confusion and verify that fair gameplay was enacted. It still will be honor based, and the receiver will be held to honor system to verify that no message was recieved from the sender.
I think it would be fun with an even number of players, where 2 countries get a comm-attack each year. The template could be drawn up before the game starts.