I'm new, so if this is in the wrong place or has already been said, sorry.
I was wondering what the possibility is of making a slave unit. (not me, can't program) I think something similar was in CIV III, but I had some huge mod, so it might not have been default. Here's my ideas:

1. Life expectancy...Could a unit be made that disappears after, say 20 turns?
2. Works twice as fast as normal workers
3. Can be built like settlers, with a minus one population loss.
4. Can also be enemy units....Destroying an enemy unit has a x% chance (use your judgement) of becoming a slave
5. They should be produced (again use judgment for number) every so often by jails, as they can (and should IMHO) in the US now.
6? A non-dying unit (with an unhappiness rating to compensate) that becomes obsolete with emancipation.

Any ideas or anyone who could make it?

Already done but I'm not shure if thouse mods have been updated to WL yet.

IMHO...

1. Life expectancy - Use the tag on a WorkBoat that causes unit to be consumed in the process of building an improvment.
2. Works twice as fast as normal workers - See above, basicaly you get 1 instant improvment kind of a whipping flavor too it
3. Can be built like settlers, with a minus one population loss - Dont think Civ4 currently has an population changes on completion of a unit, would require some SDK work
4. Can also be enemy units....Destroying an enemy unit has a x% chance (use your judgement) of becoming a slave - In anchient Society military units are either Killed OR become part of the concourers army, only the civilian population would be enslaved for example when a city is razed.
5. They should be produced (again use judgment for number) every so often by jails, as they can (and should IMHO) in the US now - Chaingangs have been phazed out and in any event even in the deep south when they were used as form of near slavery were still a trivial part of the population.
6 A non-dying unit (with an unhappiness rating to compensate) that becomes obsolete with emancipation - a unit cant have unhappiness as its not attached to an individual city and a global unhappiness effect of even 1 would be a non starter on any unit short of a nuke. Lopez just finished a mod for disbanding units once a required Civic is left.