I couldn't find any highresolution maps of Kara-Tur, possibly because it's still very popular and a recent "Trail maps of Kara-Tur" seems to have been produced.
The Maztica setting is however available free for download. It will take a bit of photoshopping to make those maps work for Dominions 2 however.
http://www.wizards.com/default.asp?x=dnd/downloads