Your not going to find an iem that sounds like any full sized open back headphone. Completely different designs that can not sound the same. Your question should be about finding a good iem with a good balanced sound in and of itself. You can't compare apples to oranges. So I'd comb the iem reviews for the qualities you like.
Thanks for the advice. So could you recommend one good balanced iem? I am indeed need one, my gf stole t51p and I travelled on daily basis "headphone-less"