For those who don’t know, Tegaki E is a blogging service where entries and comments are handwritten, ie. with a mouse (or tablet). Recently it has blossomed into a thriving art site. Think of it as a cross between deviantART and Facebook Graffiti.
The ‘Magatama Trilogy’ tag on Tegaki has many entries, so here are the search results, feel free to browse through them! (This link has also been added to the Fanart page.)
There’s a ‘Noriko Ogiwara’ tag on Tegaki as well. It includes Magatama trilogy art as well as fanart for her other novels: link