And another story I want to find, the Avengers have a sleep pile, and Tony wakes up before Steve and starts thinking about making body armour for him, and then he starts measuring his torso, and he's so deep in an engineering fugue that he doesn't realize Steve has woken up and is very confused, but also helping move his arms and stuff. Again, I think this was on AO3.
And if you have any recs, I'm definitely a Team Tony, and I like stories where he's underestimated but proves everybody wrong.
EDIT: #1 FOUND http://archiveofourown.org/works/1038183
#2 FOUND http://archiveofourown.org/works/570308/chapters/1021452
Still open for recs, though ;)