Perhaps the people who live there haven't discovered any new continents, or maybe there just aren't any. Either would explain why they wouldn't name it.
It's never referred to in game, as far as I know.
I've called it The Realm or "Wyrd's Green Earth". If I were you I'd find some nifty Celtic/Gaelic term for 'earth' or 'mother' or whatever, and spell it backwards.
Okay I got the models but now I'm too dumb to do anything with 'em
Well, I was hoping to get more suggestions since I am fairly certain, that Bungie never named it. Since the Bungieverse is a combination of Irish and Norse legends I profer these suggestions:
Burren -- "a stony place"
Thomond
Aran -- islands off of Ireland
Gard -- Anglicanized root of the Norse word for Earth, as in Midgard, Asgard, etc. hmm maybe Bungard?
I mean't really as a way to catagorize plugins, (at least for myself). So I could seperate the ones that fit in the original setting like the Ephor of Mygard, or Mazzarin's Demise and those that don't like ADT or Barbarian Valley.