This is a dogfood request to have a couple different functioning themes, with good documentation (tried with included 1.3.1 themes and failed).

Three releases (1.31, 1.4DR1/2) after a hyped feature, and there is no functioning demonstration.

Could http://confluence.atlassian.com have some spaces that demonstrate different confluence themes?

Themes and sharing via theme plug-ins could be powerful. Complaints about the layout of default theme abound, but when you attempting to create one that does more that change the color, problems abound. Basically, there are no good examples, undocumented or otherwise.