Ah those beautiful haughty bastards. I very much love these elves myself, but I'm afraid they will remain Greyhawk exclusive.
This is something we actually considered when we revised our subraces RP resources, but two things shot down their inclusion as Faerūnian elves.
The main rule to be counted as a native race of a setting, is that said race must make an appearance in one of that setting's sourcebooks. They make no appearance in any of the Forgotten Realms books. Though we can accept entries from Dragon Magazine articles, here it is indicated that their presence is an unproven rumor. That line pretty much means that their presence in your campaign setting is left at the DM's discretion. For all practical purpose we ruled that even if they were there, they'd be in such negligible number as to make them virtually inexistent from the setting.
Secondly, in regards to the Frostburn supplement, when a sourcebook isn't set in any particular setting, it is our policy to consider the sourcebook valid only to D&D 3e default setting. Which in this case is Greyhawk again.