Just stumbled on this a couple of days ago. For a DM (and aspiring author) ginning up his own home-brew campaign world, this absolutely rocks! Definitely would like a desktop version, and would be willing to pay.
In addition to being able to locate the castle, it would be nice to be able to specify some other things, like setting the paths of rivers manually, but this will definitely make creating cities, towns and villages sooooooooo much cleaner and easier for me! Thank you!