Would it be possible to add lichdom, or the ability to become a lich, to the game? Undead seems to be a fairly large theme in Skyrim and we've already had the ability to become vampires and werewolves in previous games. Why not allow us to become liches as well?

I'm not exactly sure what the requirements for it would be, or what advantages and disadvantages would be involved with becoming a powerful undead mage, but I'm sure someone here could come up with some good ideas (hopefully ones that follow whatever is available in the lore).

I had thought about this as well. As with you I am not sure what the requirements, advantages or disadvantages would be, but I like the idea of a lich automatically soul-trapping any kills made.