Unity – Workspace Indicator for More Than 4 Workspaces

There is a workaround:

First of all, install the following package:

sudo apt-get install gnome-panel

1. Then, launch a terminal and run the command gnome-panel.
2. Look for the old style workspace icons. By default, it's located at lower right corner.
3. Right click on it and choose Preferences.
4. Set the number of rows, in your case, to 2.
5. Your should get the new workspace changes. Close the window.

The only way I have found to modify the keyboard shortcuts for workspaces 5 and up in GNOME Flashback, is through a shell using the dconf command.

$ dconf read /org/gnome/desktop/wm/keybindings/switch-to-workspace-1
['<Primary>F1']

Here I read the shortcut setting for the first workspace, to get an idea about the syntax to use when setting values for the missing shortcuts. I'm using CTRL+ F1 myself.

To add shortcuts for the remaining workspaces, just modify the value returned above to match the workspace number, and use dconfto apply them:

$ dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-5 "['<Primary>F5']"
$ dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-6 "['<Primary>F6']"