I too searched for a while for an IEM to match the unrefined, rough, energetic fun of my sr60. I have to this day not found one. I have found that the RE0 has the same width of soundstage with the large bi flanges on, and I have been able to EQ it closer to the Grado sound.
If you want to take up this endeavor I would suggest two things: first, look mostly at dynamic IEMs. They seem to be closer. Second, don't be afraid to get a "bass-heavy" IEM. Bass on a full size and bass on an IEM are two very different things.