I would like to be able to bind a key to *swapping* the position of the current in the window list with the window to the left (or to the right).
Use case, sort of: I have say ten different windows open, and it turns out that I would want to group a few of them (in which I have related tasks running), moving them all together, say to the right (i.e at the end of the window list).
This is much like a terminal window (or Firefox etc) with tabs, where you can drag tabs to the left or to the right. In Gnome terminal, the key combination Ctrl-Shift-PgUp will swap the location of the current tab with the one to the left, effectively "moving" the tab within the window list.