So I knew that I wanted to create the g3p gadget using the Google Web Toolkit (GWT), since we all know writing AJAX by hand can be a pain in the ass and this is almost exactly what GWT was created for. However, when I wrote my first Google gadget for the student gadget contest back in November, I did in fact first write it without the GWT, and then later started to rewrite it using the GWT. If you want to see what these look like, here is Version 1 and Version 2 (these are links to the XML files, you can try them out by adding them to your Personalized Google homepage).
Getting the GWT app to work as a gadget is not as easy as you might think, however, and I am still not sure what the best way to do it is. I also noticed that Google suggested making this easier as number 2 of their GSoC ideas. Somebody did in fact pick up this idea (here), and so I emailed him asking if he had any suggestions for the right way to do this in the meantime. I haven't heard back yet though, so I decided to take matters into my own hands.