The children of Elrond and their choice?

[Amarie of the Vanyar]

In the Prologue to the Lord of the Rings, it is implied that Hobbits are still around, but very well hidden (as Lyta has said) [img]smilies/wink.gif[/img]

Hobbits are an unobstrusive but very ancient people, more numerous formerly than they are today (...)
Even in ancient days they were, as a rule, shy of 'the Big Folk', as they call us, and now they avoid us with dismay and are becoming hard to find
Concerning Hobbits; Prologue to LotR

About dwarves, it is said that:

And the line of Dáin prospered, and the wealth and renown of the kingship was renewed, until there arose again for the last time an heir of that House that bore the name of Durin, and he returned to Moria; and there was light again in deep places, and the ringing of hammers and the harping of harps, until the world grew old and the Dwarves failed and the days of Durin's race were ended.
The Making of Appendix A; HoME 12, The Peoples of Middle-Earth

So, it seems that the Dwarves have dissapeared from Middle-Earth.

And about Elladan and Elrohir, we know that they stayed with Celeborn in Middle-Earth after Elrond's departure to the Undying Lands. About Celeborn it is said that he sailed to the Undying Lands and that:

there is no record of the day when at last he sought the Grey Havens, and with him went the last living memory of the Elder Days in Middle-earth
Note on Shire Records; Prologue of LotR

In my opinion this means that Elladan and Elrohir either had already sailed to the Undying Lands or were already dead when Celeborn left Middle-Earth.

What makes me think that they finally sailed to the Undying Lands is this sentence that Tolkien wrote in one of his Letters:

Elrond passes Over Sea. The end of his sons, Elladan and Elrohir, is not told: they delay their choice and remain for a while.
Letter 153