I would like to suggest a system that allows multiple characters per player,
but with only one character active in the game at a given time. The new
characters would be children of the original character and their lineage would
show with finger etc. The game could control logins because character
relations would be known.
The requirements for making "children" would include a minimum level or
experience requirement. Some kind of payment or a significant offering to the
gods could also be required. Each character would only be allowed one child,
but the children might be allowed to have their own offspring once they reach
a sufficient level.
I'm sure wizards could come up with all sorts of interesting rituals for
actually making children, possibly involving more than just one parent and
possibly involving a wait period during which the parent is somehow
encumbered.