This is one of my favorite Steve/Tony tropes also. In addition to the wonderful fics already mentioned, I'd like to add:


Hidden Truths (http://talesofsuspense.net/viewstory.php?sid=284&chapter=1) by penumbren

Alter Ego (http://arysteia.livejournal.com/119806.html) by arysteia

The Sex and Identity series (http://archiveofourown.org/series/694) by muccamukk

...and two alternate universe stories where Tony's dual identity is also a key plot point:

What Lies Inside (http://archiveofourown.org/works/243242) by penumbren

Engaging the Enemy (http://archiveofourown.org/works/148861) by tsukinofaerii