Scott and Joff have produced between them a rules template for writing up the rules of fan-made Carcassonne Spin-Off expansions and variants. It's supposed to be on the member's download page, but since that is not currently available, you can download it from the link below:
Ark of the Covenent Rules TemplateCastle Rules TemplateCity Rules TemplateDiscovery Rules TemplateHunters and Gatherers Rules TemplateNew World Rules TemplateThe Kids of Carcassonne Rules Template (not available)
The base Carcassonne rules templates are also available in the Expansion forums.
