That's lentebriesje's plan, anyway, using the Worldpainter tool to create the terrain, as well as heightmaps borrowed from the National Geophysical Data Center. So far lentebriesje has already made parts of Europe, Australia and the Americas available online, though because if it's remoteness there's no Hawaii yet. Like Asia, the enormous expanse of the Pacific Ocean is still to come.
You can follow the progress of this tremendous project here on Planet Minecraft, from which you can jump off to forums that cover each of the continents lentebriesje has made. Personally, I'm also hoping we'll also get to see the Arctic and the Antarctic.