Creator of www.Planzu.com.
www.planzu.com is a GTD oriented productivity web app I've written to incorporate GTD for myself.
Current features include list building, context organizing, projects brainstorming with outcome focus.
It is in the rough cut stage but currently useful enough for every day use on from mobile to desktop.
Have a look and contact me at firstname.lastname@example.org if you're interested in trying it out.