Is there any setting/plugin/hack/workaround that will allow me to run Ubuntu with the Gnome 3.x/Gnome Shell desktop while retaining a rectangular 2x2 or n x m workspace grid instead of the default Gnome one-dimensional line-up of workspaces?
Recommended extensions for 3.32+ and 40, 41, 42, 43: Workspace Matrix.
Workspace Grid is currently not being updated, but the developer instead recommends Workspace Matrix. Workspace Matrix has nice previews of the workspaces in the displayed switcher and a lot of tweakable options.
It holds the same benefits over Frippery Panel as Workspace Grid did (see below), but is als very actively maintained.
For 3.20:
The extension Workspace Grid does the job. It is works flawlessly with 3.20.
Two benefits over Frippery Bottom Panel (which work well, cf. this answer) are:
No hacking required to remove the bottom panel.
In the overview, the grid structure is shown as the chosen two-dimensional grid. With Frippery Bottom Panel, The overview continues to shows a single strip of workspaces.
Workplace Grid. The width of the workspace overview is adjustable.
Frippery Bottom Panel. Though a workplace grid is achieved, it is not shown in the overview.
