I could see that as well, but I think that would undervalue the things you could put into a Van Richten's book. I'd make it more broadly based than just undead. Something like Van Richten's Guide to Monster Hunting.
Apart from the charm and overall pleasant presentation of the AD&D 2e Van Richten's Guides (and to a slightly lesser extent the 3e ones penned by his nieces), one of my favorite things about those books is how they offer a great deal of inspiration and options for making each monster (whether fiend, spirit, golem, therianthrope or undead) unique and memorable. Also notable is their presentation of how monster abilities can be used to invoke fear, and impotence, and how monster abilities tie to various emotional and psychological elements like rage, lust, etc.
Make the book's focus on creating memorable and awesome individuals from basic Monster Manual entries, with examples (perhaps in the form of a couple Ravenloft Darklords). Then throw in some monster hunting subclasses and organizations, and some magic items geared toward slaying specific types of monsters (especially the classic movie monsters of ghosts, vampires, mummies, golems, werebeasts, etc.), and some monster-themed backgrounds (like a former monster who was cured, or someone who's the target of a monster's obsession like a bride of dracula kind of thing) and call it a day.
I'd buy the heck out of that book.
Especially if one of the examples was Jacqueline Renier. Love her.