Taoki and Karaka are mentioned in the free online book on GWT and AppEngine development by Marius Andreiana.

The book covers also a lot of GWTP and its core examples are great illustrations for many features of the framework! It also makes use of Gin, Guice, Twig-Persist, Mockito and many other useful tools.

Go check it out: http://code.google.com/p/gwt-gae-book/

Many thanks to Marius for such a valuable resource, and congratulations on publishing it!