Your comments

Is this still going ahead?

Ideally, keyboard shortcuts would exist for everything so I never have to use a mouse, but even on a smaller scale, I'd love to have the option to just switch between windows (including closed/saved windows) with a simple alt-tab like experience (open a cut-down version of the tab window that just lists the windows, on keyup close & save the current window and open the selected one).

My ideal usecase is this: I have a number of projects on the go at once, and want to have different windows for them all, but have them closed until I want to switch between them. At the moment, I have to use the keyboard to get another window open, and then find the old window and close it. On a Mac, this is a pain because of the difference between command-tab (switch between applications) and command-` (switch between open windows of the current application)