Almost four months later I found myself wondering what TJ and his collaborators had done since then. I was surprised to find 123 public repositories in the component GitHub account. There are repositories with updates as recent as a day ago.
It's impressive how many of the repositories are truly generic, given the number of them. For example, enumerable helps iterate over sets of objects -- a very focused slice of Underscore's functionality. Other repositories are reminiscent of popular jQuery plugins, and come bundled with cut-down CSS and structural markup, as promised by TJ's post. The menu component is a good example of this.
There's also a search-api repository for the component registry.
TJ attempted to formalise the structure of components in the Component Spec. The specification includes details on a JSON manifest file, project directory structure, and submission to the registry.
It would be entirely possible to use these repositories alongside jQuery-powered client-side apps. Quite a few will work well in Node. I haven't seen many projects using these components yet, but lots of them are worth adding to your GitHub starred repositories.