The game that almost got me started on a similar project was the NES game "Dragon Warrior IV". You can play it in emulation on the PC.
It is an incredibly detailed game that would be easy for the user to edit (Just drag-and-drop tiles), and features the most sophisticated scripts and message-generation systems I've ever seen.
Eric Scharff wrote:
The reason I ask is because I'm toying with end-user world creation, and I'm looking for examples. Wonderland seems to be one of the best within-squeak examples.