Just to add my two cents. I think the three headed elephant on the Thai coat of arms represents Erawan, the steed of the Vedic god Indra. There is a strong Brahmanic Vedic undertone to Thai Buddhism and royal customs.
The kings were named Rama after the hero of the Ramayana and if I'm not mistaken, Ayyuthayya was named after Rama's Ayodhiya in India. Rama is an incarnation of Vishnu sent to the world to destroy the evil Ravana.
I think this is in keeping with the Southeast Asian concept of the Devaraja or the divine qualities associated with the ruler through which he commands prestige and reverence.
Even though the Thai king is considered above politics, his views are still very much respected by all.
It is interesting to see the crossed dagger charge which represented the states of Northern Malaya, which were once under Thai suzerainity.
On some photographs of the grand palace in Bangkok, one could see the same coat of arms, and in place of the dagger, a proper keris with several luks and a kerdas style hulu crossed with its Malay style sampir.
Methinks the trisula is Javanese.
