Description of problem:
While I have 8 virtual desktops, the Keyboard Shortcuts dialog only offers me to assign shortcuts for 'Switch to workspace N' with N ranging from 1 through 4
AFAIR this worked just fine in F16 and older

Version-Release number of selected component (if applicable):
Fedora 17 (not sure what componet the settings dialog is part of)

How reproducible:
always

Steps to Reproduce:
0. Be in forced fallback mode (this machie is slow and often used through VNC, thus I have no interest at all in the fancy mode)
1. have the Workspace Switcher visible in your taskbar
2. right click Workspace Switcher, select Preferences
3. set a number of workspaces that is > 4 (I have 8)
4. open System Settings, Keyboard, Shortcuts, Navigation

Actual results:
ability to set shortcuts for "Switch to workspace N" and "Move window to workspace N" with N between 1 and 4

Expected results:
ability to set shortcuts for "Switch to workspace N" and "Move window to workspace N" with N going from 1 to the number I set as amount of workspaces used in the Workspace Switcher

Additional info:
for others running into this (and with big kudos to mclasen), you can work around this as follows
$ gsettings list-recursively org.gnome.desktop.wm.keybindings #to see them
[...]
org.gnome.desktop.wm.keybindings switch-to-workspace-4 ['<Alt>4']
org.gnome.desktop.wm.keybindings switch-to-workspace-5 @as []
[...]
$ gsettings set org.gnome.desktop.wm.keybindings switch-to-workspace-5 "['<Alt>5']"