Tabula Rasa's system for letting players save characters and later play a copy of a different class? It was a good system, but it sadly vanished along with the rest of the game, and the upcoming Allods Online patch won't bring it back. But it will bring something very similar in the form of reincarnation, which has just been previewed on the official site. Players at level 46 or higher will be able to create a new character that's linked to the original -- and as a result, learn abilities that would otherwise be unavailable.
Characters who complete the trials necessary for reincarnation will be able to create a special Incarnation character, who shares most of a character's resources such as bag size and mounts. Incarnations are less powerful than the original while leveling, but the bonus is that both the original character and the incarnation may learn abilities from the other's class, allowing more freedom in creating a unique character. Allods Online players interested in this system can find more information on the official preview page -- it should be an interesting way to explore a different character type and earn some extra character abilities in the process.