Eiko is also my favorite I've artist! I discovered I've through her Higurashi songs, actually.
As for her recent activities, let me think back a little...
Ever since leaving I've, she's started her own label (infinity), released two singles (Onkalo and Yellow) and two collaborative mini-albums (5TEARS Vol. 1 & 2) and done some lives. This spring she also launched an official fanclub (
Shimamiya Gakuen, open to people all over the world) and recently, she seems to have taken some young singers (MAHO, ASUKA and Erika Tachibana) under her wing - she's frequently tweeting and facebooking about their activities and has written some songs for MAHO, at least. She's going to be at M3 once again this October (Yellow was released at M3 last year!) but I'm not sure yet what's coming up this year... I'm also looking forward to hearing if she's going to be at the winter Comiket this year, the 5TEARS albums were both released there and I'd love some continuation for the series.
Check her official website (
http://www.eiko-shimamiya.com/) for more info!