In my musings over Thiazia, a state based on the Kerguelen Plateau raised up some 1000m several criticisms have been levelled against this as having a population and economy worth enough to develop the forces for a realistic state that is able to play a part in world affairs.
This is down to several factors.
1. geography and location. Being perhaps a bit too far south and not ideally permissive to large scale populations.
2. lack of metals. Inhibiting population through 'gold rushes' and economic rise.
In view of this, I've speculated in what might achieve a more desirable land and come to the view that there might be scope for such if one was to interfere with continents and have a continental 'piece' pulled off a continent and dragged into an equitable zone.
Strongest case would seem during the separation of India from Antarctica and Africa, which not only already seems to have had effects on dragging Madagascar off Africa but also pulled out Sri Lanka as well....
So one could grab a section of Antarctica, say Enderby land (actually including Kempland and part of McRobertson land) off during the process and it ending up sitting north of Kerguelen but still on the Antarctic tectonic plate, much as Madagascar still sits on the African Plate.
The area north of Kerguelen being a reasonably featureless plain until one reaches the plate boundary.
This could sit somewhere between 28 degrees south and 34 degrees south, and span from 62 degrees east to 75 degrees east. This being roughly like a scaled up Isle of Wight or Majorca in shape. In total beneath the water a rough lenticular shape.
Such a landmass doesn't significantly alter the balance of landmass to water, and ought to not majorly interrupt the flow of Indian Ocean currents.
Antarctica ought to still be a frozen waste covered in vast quantities of ice, just a bit smaller....
Thus it would be far 'north' enough to be more equitable without being tropical and/or desert, nor too far 'south' enough to be wracked by the roaring 40's and antarctic storms.
It would also being truely continental in geology, posses quantities of metals (including precious metals), minerals and other such resources.....possibly precious stones.
Still the potential for good deposits of coal as well.
Chief problems are...
Impact on southern hemisphere's climate might still be too great, especially on Australia.
It's more than likely humans will arrive on the landmass at least 2000 BC, as per Madagascar and proper settlement by 350 to 550 AD, likely these are Austronesian peoples again as per Madagascar. This permits a long period of development and 'taming' of the landmass, geography, flaura and fauna (marsupials).
This creates a whole language and culture conundrum.
One can envision a series of proto-states emerging on the landmass.
Persian and Arab explorers could discover the place.
European conquest would follow from the 1500's onward, and presumably various powers vie for it's control, starting with the Portuguese and either ending up in Dutch or British hands. Though one cannot entirely rule out the natives finding a way for some or all of the land to stay free of European control....
But this does obviate the limitations of basing population rises on colonisation and 'gold rushes'.