Doing some quick focus at exotic scripts around, we stumbled upon this one from 8th century CE India. The pallava script derived from the Proto Brahmi script seems to have a later influence on the orthographic evolution of South East asian scripts including Khmer and writing systems including Sinhala have its influence. Apparently used as the prevalent script to write Sanskrit prior to the taking over of Nagari/Devanagari scripts post 10th century CE.
Image: Hand crafted image in Pallava script by Ms. Jayalakshmi P Iyangar with the text jayaM vedasya sArathiM.
PS: Albeit a later developed script, Khmer does show a good degree of similarity with Pallava script. You could check out Google’s Swannaphum Webfont or Freehand as good free flowing unicode compliant type faces for Khmer.