Mantic Games have released their Undead Command figures as individual products.
From their announcement:
This month sees the the release of 3 brand new box-sets for our Undead range: The Zombie Regiment with Command; The Ghoul Regiment with Ghast; and the Ghoul Regiment.
We have noticed though that there have been repeated requests for the new components to be available separately, and since we listen to what you guys want so we have decided to release Zombie and Ghoul upgrade kits.
First we have the Zombie Command: containing all the plastic and metal components needed to make a Champion, Standard and Musician as well as some head swaps and new conversion parts.
Second we have the Ghoul Ghast: This upgrade kit gives you 2 plastic ghouls and the Ghast conversion part, which allows you to add more death and mayhem to the front rank of your Ghoul Hordes.