OK, I just put the finishing touches on another 9 Slingslaves, which brings me to over 500 points in slaves:
Slave Taskmaster and 4 Guardslaves
Total: 518 points.
I have another 23 Spearslaves to do, which will bring me to 748 points for the mighty Slave horde. That's going to be 6 squads on the table and 61 units of doom comin' at ya!