It is finished BTW a nice addition to the next version of GoodMod.
Technically the slic code will destroy the city first than it creates a enemy settler (of the civ from that you just conquered the city) and a slaver with your nationality that enslaves the settler. The new slave will be added to one of your cities (therefore the just conquered city must be destroyed before in order to avoid sending the slaves back to this city). Than the loop will start again with creating settler, creating slaver, enslaving settler, disbanding slaver as often as high the city population of the conquered city was.
For a player it will look like that the population is driven out of the right into the arms of your slavers.

BTW nice special effect this enslaving fest in front of the walls of your city. But be cautious to many slaves can cause some revolts.
This slic file is designed for the default game and GoodMod but it is also compartible with MedPack2 and Cradle. The new city capture option is available until someone built the Emancipation Act wonder, that frees all slave. Afterwards the Emancipation Act was built it is replaced by the resettle option. Further installation notes are inside the slic file. For download visit my homepage or click
here.
-Martin