Hello, thanks for sharing your thoughts about the app. A -almost- invisible tab icon is a great idea and I will get on it soon.
As for the shortcut, do you mean having it instead of the tab, so you can launch the gesture field from certain home screens only?
Yup! A shortcut or activity that launches the gesture field. In suggesting it since there are a variety of apps that allow you to launch shortcuts or activities from any screen =]
I 2nd the request for a shortcut. I would also be happy with an invisible or pure black tab icon.
Let me say, however, that this is a great concept and I hope you continue to develop it. You should add a "Donate" button so people can really show their support.