Comment 9 for bug 639633

Workspaces can now be changed in CCSM, under "General Options" > "Desktop Size" > Horizonthal/Vertical Virtual Size.
It works at runtime, and I think that a separate cinfiguration window is not needed anymore, cause this is an advanced task and for this type of task CCSM would suffice.

I think there is no reason why a normal user should change workspaces number and screw up unity.