I saw a character concept somewhere and even built it for a fate game that lasted all of 2 sessions where the character doesn't just put on a disguise but convinces takes the disguises role to the extreme. For example if he disguised himself as a lonestar officer he would actively patrol his area and make arrests, take bribes, whatever, though usually keep to whatever task he is wearing the disguise for. Leonardo DiCaprio's character in Catch Me if You Can does this to a certain extent when he pass's the bar for his lawyer persona and gets himself over his head as the doctor.
The questions are: How would you do this in sr4 and with cyberdecks and SINs is it even possible? The closest thing I can find is the deep cover quality that covers some of the concept, but not all. This should go a bit past just rol.play and have a mechanical bonus or penalty. For example the fate character had the aspect The Clothes Make the Man where if you spend a fate point (invoking the aspect) you gain a bonus to a disguise or deceit check but you could gain a fate point by taking a Compel and playing out role of your disguise.