I'm uncertain if there is a topic around currently addressing this suggestion but...
As the feat says:
"Construct Essence -
You are on the path to becoming a self-forged, augmenting yourself by replacing some of your weak flesh. You are still considered your original race (at this time), gaining 50% healing from Repair spells but suffering a -25% penalty to positive energy healing. In addition, you now take 50% damage from rust effects. "
I submit for consideration the idea of adding some sort of flavorful cosmetic effect to be applied to characters who take this feat not like that of dragonmarks, but more construct-like. Like dragonmarks, players should have the option of being able to turn them on/off.