I always offer this tutorial: http://www.urbanthreads.com/tutorial...=Tattoo+Tights
Get some nude colored tights, engineer a way to wear as sleeve, and then either stretch them on something else, or just pull em on yourself and get your friend to draw away. Ed Hardy clothing basically did this at one point, offering tshirts with fake sleeve tattoos that were just printed on a long mesh sleeve that would seem invisible unless you looked closely or touched it. (Remember that episode of Big Bang Theory when Howard and Raj tried to be goth to get into a club?)
And then I second animenerd's suggestion on the bandaged arm by making it an armband of sorts and disguising the hook and eye closures with an extra strip.
Costume Con - Kili in a dress
Atomic Lollipop - Come visit me at the Make-Your-Own-Button free craft booth!
Polar Chill - check out my costume DIY panel and workshop
FanExpo - Iron Man Mark VII version 2, Pacific Rim Jaeger pilot?
FanExpo - fem!Iron Man Mark VII - The Iron Man Armor Project
Atomic Lollipop - Vanellope von Schweetz; raver!Sailor Mars