itch.io

In the non-itch version you can generate larger cities by editing the size parameter in the url:

http://fantasycities.watabou.ru/?size=100&seed=305719153&hub=0&random=0&citadel=1&plaza=1&temple=1&walls=0&shantytown=1&river=0&coast=0

They don't look too good, that's why there is no UI for generating cities this big.