Having just finished the game, I took a look at the files to see if there was any easy way to modify them, putting in new graphics and text. While on North Island I decided the cheery overworld music was inappropriate, and replaced that song with "Another World" from Chrono Cross -- easy, since the music files are all just MIDIs. The "scripts" file in the main directory was partly readable in Notepad but crashed the game when altered even a little.
The graphics are apparently a combination of pre-drawn 3D scenes (like the dam), little square tiles (for the overworld), and diamond "isometric" tiles (eg. Ferret Village). The last two would probably be easiest to change and rebuild into new maps.
I suspect that a hex editor, or the editing tools developed for X-Com: UFO Defense, would let people customize the game to some extent. Anyone care?
Yea I also was thinking mabye I could make an unnoffical sequal to ITE as a mod for the origional.