Rails RESTfull API Documentation

I'm searching for a Documentation Framework that supports the following features:

• Generated from Code Comments
• Searchable
• Styling customizable
• NTH: Linked references (If i reference a class somewhere class name should be linked to class documentation)

I want to use it to document an RESTfull API i'm working on

I know about YARDoc, but would be nice to gather some alternatives

Matt Silverman created a pretty comprehensive lists of what is available out there now for gen'ing docs from code.

http://www.mattsilverman.com/2013/02/tools-to-generate-beautiful-api-documentation.html