As things currently stand, I'm going to be devoting my energies to the "lich" story here, unless something particularly amazing hits me about the other story.
First, no, I don't have a title yet. That will certainly come in its own time. I've been somewhat anal before about feeling the need to have a title before I embark too far in writing, but now I feel fine with letting it happen on its own.
Also, I'll probably never actually call these undead creatures "liches" in the story. I want to leave that out of things. I fear the term will try to prevent me from following certain avenues the plot or the creature type could move into, that I might tie myself too closely to something.
The system of magic, at its most basic, relies upon the binding of spirits and souls into objects. These binds could be drawn in ink on paper, or carved into iron. Or any other way one could think of to make them -- lay them in leaves upon the ground, or make them in scarring the flesh of a captive. Magicians won't be the sort of fire-and-lightning throwing mages of game fantasy or series like the Wheel of Time or the Runelords. Properly inventive magicians would be able to give themselves some special abilities and defenses, though. And servants. No summoning demons or angels, gods or ancient warriors, but undead can be created...
Undead exist primarily as zombies, who are those whose souls have been returned to their corpses within minutes of death, though the bind would not bring the body to full vitality, nor could the soul control the body. Instead, the body rots slowly while acting under the command of the one who sealed the bind on the body. Obviously, this sort of magic is considered utterly reprehensible.
The point of all that? Basically, the protagonist's ultimate transformation into a lich requires the creation or discovery of the secrets of a specific bind. This bind is used when the magician is still alive, and instead of trapping his soul inescapably within his body, it connects the soul to an object of some significance to the magician. With his soul suspended "between" his body and the object, the magician is neither dead nor alive. Presumably the bind is made solely upon the object in some hidden spot, for even a chance cut of the magician's undead flesh could break the bind if it was on him. He could also control the workings of his body even if it was dismembered, allowing him to quite probably reassemble himself even should all his limbs be cut off and he gets beheaded.
The object of choice for the protagonist has already been determined, as well. See, this novel is also meant to be something of a homage to Oscar Wilde's "The Picture of Dorian Gray." This bit I only just hit upon today, actually, and it fits quite well. The protagonist's object of choice as vector for his immortality is, in fact, a portrait of himself.
He's something of a "gentleman magician," and a bit vain and self-indulgent. He's also madly afraid of death. While not the trigger for his obsessive quest to find the secrets of undeath, the portrait is something of a kick in the shin, because the painter accurately portrayed his appearance, which the protagonist in his narcissism thinks looks too old by a few years and gray hairs. Of course, in contrast to "Dorian Gray" and in line with the real world, the painting stays the same while the protagonist changes, showing signs of age and wear and illness as his obsessive search starts to eat at him.
I still need to come up with a name for the protagonist. I want something mostly normal but just a touch fitting with his magical nature. It's really a shame that Susanna Clarke has already taken "Jonathan Strange" as the name of a lead character in her published novel, "Jonathan Strange & Mr Norrell," because that name is just utterly perfect. Though it's a quite excellent novel, as well, so my "annoyance" is all in jest.