It is fascinating to me too. Buhid is another one derived from Kawi; it hasn't died out and is still apparently in use in the Philippines. Needless to say, these abugidas and those of Indonesia (Batak, Balinese etc) are extremely under-represented in the type world. Hopefully that will change in time to stop these scripts from fading into obsolescence.
In a recent web search, inspired by the thread here about a Devanagari font from Adobe, I came across this fascinating web site:
http://nordenx.blogspot.ca/2012_04_01_archive.html
In the 1600s and before, the writing system used in the Philippines for Tagalog was, like those of Thailand, Burma, and Tibet, an abugida derived, like Devanagari, from the ancient Brahmi script.
EDIT: My first search result was probably
http://istoryadista.blogspot.ca/2011/09/baybayin-way-of-writing-in-our-own.html
Another important site, with different fonts, is
