Nice twist Alain, but I'm sure that would be too cruel and not worth the effort in keeping him alive. I do however agree with that they should start at level 1. Perhaps leave it the way it is as far as starting levels go, level 1 for goblins, level 4 for giants, etc.
In the case when your Personal Slave dies, you may replace him. However, you must level him all the way back up again. This would make Personal Slaves a lot more special to keep from dying, but also keep it from a once-dead-always-dead type. We all know thats not fun, for all of us who've been to servers like that.
However, what shall we do involving a slave dying and a character raising him? I'd say raise the Corpse Decay Time for slaves to 5 or 10 minutes. I think that would work.