Take your top 50 artists. For each of these artists, collect the top 20 similar artists (where the artist itself is the #1 most similar). The resulting number of unique artists is your super-eclectic score. You can compute your own score at http://anthony.liekens.net/pub/scripts/last.fm/supereclectic.php
My super-eclectic score is currently
657/1000
The most similar artists for my profile are 矢井田瞳 (8), Nell (7), Loveholic (7), 島谷ひとみ (7), Every Little Thing (7), 鈴木あみ (7), 浜崎あゆみ (6), 梶浦由記 (6), hitomi (6), 川井憲次 (5)