While I realise this topic is meant in jest, have you noticed the existence of the ritual Call Winged Messenger, which for a mere 3 mana (mastered) can send a message anywhere in the physical world?
Someone else has pointed out that one can use the target of the trods. Use them as a sort of inter-nation network. An inter-net as it were.
Target a message on the trods, then anyone in the empire can read it via Skein of Ages, as well as all other messages that have appeared previously, because Skein of Ages.
I believe Winged Messenger isn’t quite instant, partly because physrep is ref bootleather?
For a cheaper version, hand letter to a passing Navarr, it’ll probably get to intended recipient within a few weeks.
Practically speaking, WM gets to a remote target within about 15 minutes. It takes rather longer to get to a PC, unless they happen to be in a predictable place.
You need to send out a sufficent number of people to the place you want to communicate with.
5 people per character you want to send,
each of them having the Arcane Mark of a different conclave order.
2 ^ 5 is 32 which is enough to encode letters and basic punctuation,
by pre-assigning a letter / punctuation symbol to each combination of arcane marks.
When you are ready to send your message, you get the senate to dissolve some of the arcane orders,
to leave the combination of arcane marks on the people you sent out of the characters you want to send.
Arcane marks are removed instaneously when the senate dissolves the Arcane order.
This is therefore much faster and more reliable time wise than attempting to use the Winged Messenger ritual,
which could take several days.
The message arrives instantly and be decoded by the simple spell of detect magic.
It would require significant work, on the scale of the Blood Red Roads or the original Trod project (y’know, the one that’s still ongoing). This is a world in which Civ-style Wonders exist, and trying to build them is Big and Clever.