In general, your deployments show up sequentially in the order that you place the troops. *Note, I think this may appear slightly differently in Unity when orders are lumped together, though I still think they appear in the order list in the same order.
Generally, I see a lot of people that appear to place all of their deployment orders for in-the-fog expansion first, then, whatever they have left over, they plop down on the front that is visible with the enemy.
When viewing the turn, deployments then happen in the same manner as doing attack/transfer orders, so you can then get a count of how many deployment orders the other player made, which gives you an indication of how many other armies that player is deploying behind the fog. For example, with 2 neutrals, you could assume that each deployment order that you don't see in the list of order deployments before his final deployment, you can assume he placed 2 armies. So in this example, if you didn't see 10 of his deployment orders and he plopped down 30 armies against you, you could safely assume he had at least 50 income that turn.
If the person attacks many from one, then this could increase the implied armies b/c each deployment order would take more than 2 armies to support attacking many territories from one.
This tactic does take a little extra time to count up, and the results of this don't show up in the statistic graphs.
One thing I do when deploying troops is to always plop down 1 initial army in territories that border the enemy, then make all of my expansion deployments, then with any leftovers, deploy them where I want to fight. Sometimes I eliminate the +1 that I initially put there as the deployment order placeholder if I indeed don't want to deploy there.
I feel that this at least hides any potential information about my income that the other player may derive based on when he sees me deploy.