[Mithalwen]

I have been pondering this because I have an elvish corpse to dispose of in a RPG (though I am going with the possibly uncanonical wished of the player concerned for that and cremating him).

I don't know whether it is one of the latent Catholic elements in the works (The Vatican only relaxed its ban on cremation in 1967) but cremation is seldom the fate of good characters (the burned dwarves of Nanduhirion being the exception, and presumably Gil Galad and Elendil if they were frazzled in combat with Sauron). Good characters get buried in grave or tomb. There was quite a bit about death customs in the discussion of the Breaking of the Fellowship episode of the Radio Series which might interest those not otherwise interested in that thread.

However I am sure I read somewhere in Home that an Elvish body even unburied would go to dust quickly - I think it is on the development of the idea of Elvish rebirth. However some bodies (those of Luthien & Miriel for example) do not decompose - though clearly those are both unusual circumstances.

The different relationship with elves of body and soul - and indeed the different relationship with death probably affects the funeral rites. I imagine that there might be a great variance between the Exiled Noldor (for whom the Valar and Valinor were a matter of fact not faith - as Terry Pratchett said about the discworld gods, saying they believed in them would be like us saying we believed in the postman, the Sindar who had a lesser immediate experience, and the Silvan elves for whom such things are not real in the same way - think of Haldir's conversation with Merry. Presumably the elves of Thranduil, not living under the rule of a living link with Valinor found the the idea of passing West as even more remote and unappealing. Legolas implies that he has interpreted Galadriel's message as "speaking of his death".

Therefore it is likely that the Silvan elves of Mirkwood might regard death more seriously than say the Noldor and consequently have the most elaborate funeral rites since the death would seem more drastic.

I cannot find a reference to a non-burial funeral (including cairns and mounds with graves) Some are more elaborate than others - Beleg is buried in a shallow grave. The graves seem to hold a residual power. Glorfindel's cairn in a barren landscape yields grass and the yellow flowers enblematic of his house while "the green grave of Finrod.. remained inviolate, until the land was changed... but Finrod walks with Finarfin, his father beneath the trees in Eldamar".