I hate to bring this disscution back up again, but I cant help but feel that Antarctica was shot down rather quickly.
I personally don't have a problem running STK on either my (cheepo) notebook or high end PC, though they use vastly different settings.
I feel that Antarctica would be the best option for MT if another engine were to be used, as it is based off of Irrlicht so it would be the easiest to port to.
(Also, my notebook is half broken, still)