The mysterious larger genre of Flying head witch films

Although Pete Tombs' book 'Mondo Macabro' only mentions 1977's 'Witch With Flying Head' and this one as far as Penanggalan (the Chinese name for a witch with a flying head) films go, another one from 1967 titled simply 'Penanggalan,' is obviously earlier, but who has ever seen it, or knows where to get a copy of it in some format?
There is also an entire genre of these films in Indonesia and Thailand, and I have film posters for a dozen of them, which were picked up over the years by a friend on business trips in Thailand,even though most U.S. and European film critics seem to be only aware of 'Mystics in Bali' (Leák-1981) and 'Witch with Flying Head' (1977).
Thai people at Thai video stores in the U.S. are aware of this genre, though none I have spoken with seem to have any tapes or laserdiscs of them, claiming it was a big fad in the late seventies through the early nineties. They have referredto these films as 'P'Graseau,' 'Pee Graseau,' Kraseau, Krasue and any combination of these names and various spellings.
With the release last year of 'Krasue,' however, it is obvious that Southeast Asia is still in the business of making flying-head witch flicks.
When will someone with the resources open up this veritable hidden treasure chest of weird Asian cinema for the rest of the world?
If anyone has any ideas, e-mail me at: [email protected]