i3tag provides dynamic workspaces for i3, à la wmii.
To use it, you'll want to use key bindings like the following in your i3
configuration:
bindsym $mod+t exec i3tag switch
bindsym $mod+1 exec i3tag switch 1
bindsym $mod+2 exec i3tag switch 2
bindsym $mod+3 exec i3tag switch 3
bindsym $mod+4 exec i3tag switch 4
bindsym $mod+5 exec i3tag switch 5
bindsym $mod+6 exec i3tag switch 6
bindsym $mod+7 exec i3tag switch 7
bindsym $mod+8 exec i3tag switch 8
bindsym $mod+9 exec i3tag switch 9
bindsym $mod+Shift+t exec i3tag move
bindsym $mod+Shift+1 exec i3tag move 1
bindsym $mod+Shift+2 exec i3tag move 2
bindsym $mod+Shift+3 exec i3tag move 3
bindsym $mod+Shift+4 exec i3tag move 4
bindsym $mod+Shift+5 exec i3tag move 5
bindsym $mod+Shift+6 exec i3tag move 6
bindsym $mod+Shift+7 exec i3tag move 7
bindsym $mod+Shift+8 exec i3tag move 8
bindsym $mod+Shift+9 exec i3tag move 9
i3tag switch <workspace> will look for an existing workspace whose name
begins with the prefix <workspace>:, and focus that workspace. If none is
found, then a workspace named <workspace> will be created and focused.
Without a workspace argument, i3tag switch will prompt (using rofi) for
a workspace to switch to. The move variant of the commands are analogous, but
move the currently focused container to the workspace, instead of focusing it.
This allows behavior almost identical to the default $mod[-Shift]-t and
$mod[-Shift]-<N> from wmii.